compound assignment - Page 67

Different behavior of functors (copies, assignments) in VS2010 (compared with VS2005)

- by Patrick

When moving from VS2005 to VS2010 we noticed a performance decrease, which seemed to be caused by additional copies of a functor. The following code illustrates the problem. It is essential to have a map where the value itself is a set. On both the map and the set we defined a comparison functor (which is templated in the example). #include <iostream> #include <map> #include <set> class A { public: A(int i, char c) : m_i(i), m_c(c) { std::cout << "Construct object " << m_c << m_i << std::endl; } A(const A &a) : m_i(a.m_i), m_c(a.m_c) { std::cout << "Copy object " << m_c << m_i << std::endl; } ~A() { std::cout << "Destruct object " << m_c << m_i << std::endl; } void operator= (const A &a) { m_i = a.m_i; m_c = a.m_c; std::cout << "Assign object " << m_c << m_i << std::endl; } int m_i; char m_c; }; class B : public A { public: B(int i) : A(i, 'B') { } static const char s_c = 'B'; }; class C : public A { public: C(int i) : A(i, 'C') { } static const char s_c = 'C'; }; template <class X> class compareA { public: compareA() : m_i(999) { std::cout << "Construct functor " << X::s_c << m_i << std::endl; } compareA(const compareA &a) : m_i(a.m_i) { std::cout << "Copy functor " << X::s_c << m_i << std::endl; } ~compareA() { std::cout << "Destruct functor " << X::s_c << m_i << std::endl; } void operator= (const compareA &a) { m_i = a.m_i; std::cout << "Assign functor " << X::s_c << m_i << std::endl; } bool operator() (const X &x1, const X &x2) const { std::cout << "Comparing object " << x1.m_i << " with " << x2.m_i << std::endl; return x1.m_i < x2.m_i; } private: int m_i; }; typedef std::set<C, compareA<C> > SetTest; typedef std::map<B, SetTest, compareA<B> > MapTest; int main() { int i = 0; std::cout << "--- " << i++ << std::endl; MapTest mapTest; std::cout << "--- " << i++ << std::endl; SetTest &setTest = mapTest[0]; std::cout << "--- " << i++ << std::endl; } If I compile this code with VS2005 I get the following output: --- 0 Construct functor B999 Copy functor B999 Copy functor B999 Destruct functor B999 Destruct functor B999 --- 1 Construct object B0 Construct functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Copy object B0 Copy functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Copy object B0 Copy functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Destruct functor C999 Destruct object B0 Destruct functor C999 Destruct object B0 --- 2 If I compile this with VS2010, I get the following output: --- 0 Construct functor B999 Copy functor B999 Copy functor B999 Destruct functor B999 Destruct functor B999 --- 1 Construct object B0 Construct functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Copy object B0 Copy functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Copy functor C999 Assign functor C999 Assign functor C999 Destruct functor C999 Copy object B0 Copy functor C999 Copy functor C999 Copy functor C999 Destruct functor C999 Destruct functor C999 Copy functor C999 Assign functor C999 Assign functor C999 Destruct functor C999 Destruct functor C999 Destruct object B0 Destruct functor C999 Destruct object B0 --- 2 The output for the first statement (constructing the map) is identical. The output for the second statement (creating the first element in the map and getting a reference to it), is much bigger in the VS2010 case: Copy constructor of functor: 10 times vs 8 times Assignment of functor: 2 times vs. 0 times Destructor of functor: 10 times vs 8 times My questions are: Why does the STL copy a functor? Isn't it enough to construct it once for every instantiation of the set? Why is the functor constructed more in the VS2010 case than in the VS2005 case? (didn't check VS2008) And why is it assigned two times in VS2010 and not in VS2005? Are there any tricks to avoid the copy of functors? I saw a similar question at http://stackoverflow.com/questions/2216041/prevent-unnecessary-copies-of-c-functor-objects but I'm not sure that's the same question. Thanks in advance, Patrick

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Entry lvl. COBOL Control Breaks

- by Kyle Benzle

I'm working in COBOL with a double control break to print a hospital record. The input is one record per line, with, hospital info first, then patient info. There are multiple records per hospital, and multiple services per patient. The idea is, using a double control break, to print one hospital name, then all the patients from that hospital. Then print the patient name just once for all services, like the below. I'm having trouble with my output, and am hoping someone can help me get it in order. I am using AccuCobol to compile experts-exchange does not allow .cob and .dat so the extentions were changed to .txt The files are: the .cob lab5b.cob the input / output: lab5bin.dat, lab5bout.dat The assignment: http://www.cse.ohio-state.edu/~sgomori/314/lab5.html Hospital Number: 001 Hospital Name: Mount Carmel 00001 Griese, Brian Ear Infection 08/24/1999 300.00 Diaper Rash 09/05/1999 25.00 Frontal Labotomy 09/25/1999 25,000.00 Rear Labotomy 09/26/1999 25,000.00 Central Labotomy 09/28/1999 24,999.99 The total amount owed for this patient is: $.......... (End of Hospital) The total amount owed for this hospital is: $......... enter code here IDENTIFICATION DIVISION. PROGRAM-ID. LAB5B. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT FILE-IN ASSIGN TO 'lab5bin.dat' ORGANIZATION IS LINE SEQUENTIAL. SELECT FILE-OUT ASSIGN TO 'lab5bout.dat' ORGANIZATION IS LINE SEQUENTIAL. DATA DIVISION. FILE SECTION. FD FILE-IN. 01 HOSPITAL-RECORD-IN. 05 HOSPITAL-NUMBER-IN PIC 999. 05 HOSPITAL-NAME-IN PIC X(20). 05 PATIENT-NUMBER-IN PIC 99999. 05 PATIENT-NAME-IN PIC X(20). 05 SERVICE-IN PIC X(30). 05 DATE-IN PIC 9(8). 05 OWED-IN PIC 9(7)V99. FD FILE-OUT. 01 REPORT-REC-OUT PIC X(100). WORKING-STORAGE SECTION. 01 WS-WORK-AREAS. 05 WS-HOLD-HOSPITAL-NUM PIC 999 VALUE ZEROS. 05 WS-HOLD-PATIENT-NUM PIC 99999 VALUE ZEROS. 05 ARE-THERE-MORE-RECORDS PIC XXX VALUE 'YES'. 88 MORE-RECORDS VALUE 'YES'. 88 NO-MORE-RECORDS VALUE 'NO '. 05 FIRST-RECORD PIC XXX VALUE 'YES'. 05 WS-PATIENT-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-HOSPITAL-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-PAGE-CTR PIC 99 VALUE ZEROS. 01 WS-DATE. 05 WS-YR PIC 9999. 05 WS-MO PIC 99. 05 WS-DAY PIC 99. 01 HL-HEADING1. 05 PIC X(49) VALUE SPACES. 05 PIC X(14) VALUE 'OHIO INSURANCE'. 05 PIC X(7) VALUE SPACES. 05 HL-PAGE PIC Z9. 05 PIC X(14) VALUE SPACES. 05 HL-DATE. 10 HL-MO PIC 99. 10 PIC X VALUE '/'. 10 HL-DAY PIC 99. 10 PIC X VALUE '/'. 10 HL-YR PIC X VALUE '/'. 01 HL-HEADING2. 05 PIC XXXXXXXXXX VALUE 'HOSPITAL: '. 05 HL-HOSPITAL PIC 999. 01 HL-HEADING3. 05 PIC X(7) VALUE "Patient". 05 PIC X(3) VALUE SPACES. 05 PIC X(7) VALUE "Patient". 05 PIC X(39) VALUE SPACES. 05 PIC X(7) VALUE "Date of". 05 PIC X(3) VALUE SPACES. 05 PIC X(6) VALUE "Amount". 01 HL-HEADING4. 05 PIC X(6) VALUE "Number". 05 PIC X(4) VALUE SPACES. 05 PIC X(4) VALUE "Name". 05 PIC X(18) VALUE SPACES. 05 PIC X(10) VALUE "Service". 05 PIC X(14) VALUE SPACES. 05 PIC X(8) VALUE "Service". 05 PIC X(2) VALUE SPACES. 05 PIC X(5) VALUE "Owed". 01 DL-PATIENT-LINE. 05 PIC X(28) VALUE SPACES. 05 DL-PATIENT-NUMBER PIC XXXXX. 05 PIC X(21) VALUE SPACES. 05 DL-PATIENT-TOTAL PIC $$$,$$$,$$9.99. 01 DL-HOSPITAL-LINE. 05 PIC X(47) VALUE SPACES. 05 PIC X(16) VALUE 'HOSPITAL TOTAL: '. 05 DL-HOSPITAL-TOTAL PIC $$$,$$$,$$9.99. PROCEDURE DIVISION. 100-MAIN-MODULE. PERFORM 600-INITIALIZATION-RTN PERFORM UNTIL NO-MORE-RECORDS READ FILE-IN AT END MOVE 'NO ' TO ARE-THERE-MORE-RECORDS NOT AT END PERFORM 200-DETAIL-RTN END-READ END-PERFORM PERFORM 400-HOSPITAL-BREAK PERFORM 700-END-OF-JOB-RTN STOP RUN. 200-DETAIL-RTN. EVALUATE TRUE WHEN FIRST-RECORD = 'YES' MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN MOVE 'NO ' TO FIRST-RECORD WHEN HOSPITAL-NUMBER-IN NOT = WS-HOLD-HOSPITAL-NUM PERFORM 400-HOSPITAL-BREAK WHEN PATIENT-NUMBER-IN NOT = WS-HOLD-PATIENT-NUM PERFORM 300-PATIENT-BREAK END-EVALUATE ADD OWED-IN TO WS-PATIENT-TOTAL. 300-PATIENT-BREAK. MOVE WS-PATIENT-TOTAL TO DL-PATIENT-TOTAL MOVE WS-HOLD-PATIENT-NUM TO DL-PATIENT-NUMBER WRITE REPORT-REC-OUT FROM DL-PATIENT-LINE AFTER ADVANCING 2 LINES ADD WS-PATIENT-TOTAL TO WS-HOSPITAL-TOTAL IF MORE-RECORDS MOVE ZEROS TO WS-PATIENT-TOTAL MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM END-IF. 400-HOSPITAL-BREAK. PERFORM 300-PATIENT-BREAK MOVE WS-HOSPITAL-TOTAL TO DL-HOSPITAL-TOTAL WRITE REPORT-REC-OUT FROM DL-HOSPITAL-LINE AFTER ADVANCING 2 LINES IF MORE-RECORDS MOVE ZEROS TO WS-HOSPITAL-TOTAL MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN END-IF. 500-HEADING-RTN. ADD 1 TO WS-PAGE-CTR MOVE WS-PAGE-CTR TO HL-PAGE MOVE WS-HOLD-HOSPITAL-NUM TO HL-HOSPITAL WRITE REPORT-REC-OUT FROM HL-HEADING1 AFTER ADVANCING PAGE WRITE REPORT-REC-OUT FROM HL-HEADING2 AFTER ADVANCING 2 LINES. WRITE REPORT-REC-OUT FROM HL-HEADING3 AFTER ADVANCING 2 LINES. 600-INITIALIZATION-RTN. OPEN INPUT FILE-IN OUTPUT FILE-OUT *159 ACCEPT WS-DATE FROM DATE YYYYMMDD MOVE WS-YR TO HL-YR MOVE WS-MO TO HL-MO MOVE WS-DAY TO HL-DAY. 700-END-OF-JOB-RTN. CLOSE FILE-IN FILE-OUT.

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Returning new object, overwrite the existing one in Java

- by lupin

Note: This is an assignment. Hi, Ok I have this method that will create a supposedly union of 2 sets. i mport java.io.*; class Set { public int numberOfElements; public String[] setElements; public int maxNumberOfElements; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { this.numberOfElements = numberOfE; this.setElements = new String[setE]; this.maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { if (setElements[i] != null) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; int len = newYtemparray.length + newXtemparray.length; Set temp = new Set(0,len,len); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newYtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newXtemparray.length; j++) { temp.add(newXtemparray[j]); } return temp; } Set difference(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; int len = newYtemparray.length + newXtemparray.length; Set temp = new Set(0,len,len); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newXtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newYtemparray.length; j++) { int retval = temp.findElement(newYtemparray[j]); if( retval != -1 ) { temp.remove(newYtemparray[j]); } } return temp; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(0,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element sixb is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); //setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); //setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); //setA.printSet(); Set setB = new Set(0,10,10); setB.add("b"); setB.add("z"); setB.add("x"); setB.add("y"); Set setC = setA.union(setB,setA); System.out.println("Elements of setA"); setA.printSet(); System.out.println("Union of setA and setB"); setC.printSet(); } } The union method works a sense that somehow I can call another method on it but it doesn't do the job, i supposedly would create and union of all elements of setA and setB but it only return element of setB. Sample output follows: java SetDemo Enter string element to be added hello You entered hello Set size is: 10 Set is empty? false Element sixb is member of setA? -1 Set is full? true Element b located on index: 2 Set size is: 9 Elements of setA Member elements on index: 0 hello Member elements on index: 1 world Member elements on index: 2 six Member elements on index: 3 seven Union of setA and setB Member elements on index: 0 b Member elements on index: 1 z Member elements on index: 2 x Member elements on index: 3 y thanks, lupin

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Java constructor and modify the object properties at runtime

- by lupin

Note: This is an assignment Hi, I have the following class/constructor. import java.io.*; class Set { public int numberOfElements = 0; public String[] setElements = new String[5]; public int maxNumberOfElements = 5; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; Set temp = new Set(1,20,20); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newXtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newYtemparray.length; j++) { temp.add(newYtemparray[j]); } return temp; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(1,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element six is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); setA.printSet(); Set setB = new Set(0,10,10); Set SetA = setA.union(setB,setA); SetA.printSet(); } } I have two question here, why I when I change the class property declaration to: class Set { public int numberOfElements; public String[] setElements; public int maxNumberOfElements; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } I got this error: \ javaprojects>java SetDemo Enter string element to be added a You entered a Exception in thread "main" java.lang.NullPointerException at Set.findElement(Set.java:30) at Set.add(Set.java:43) at SetDemo.main(Set.java:169) Second, on the union method, why the result of SetA.printSet still printing null, isn't it getting back the return value from union method? Thanks in advance for any explaination. lupin

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Higher order function « filter » in C++

- by Red Hyena

Hi all. I wanted to write a higher order function filter with C++. The code I have come up with so far is as follows: #include <iostream> #include <string> #include <functional> #include <algorithm> #include <vector> #include <list> #include <iterator> using namespace std; bool isOdd(int const i) { return i % 2 != 0; } template < template <class, class> class Container, class Predicate, class Allocator, class A > Container<A, Allocator> filter(Container<A, Allocator> const & container, Predicate const & pred) { Container<A, Allocator> filtered(container); container.erase(remove_if(filtered.begin(), filtered.end(), pred), filtered.end()); return filtered; } int main() { int const a[] = {23, 12, 78, 21, 97, 64}; vector<int const> const v(a, a + 6); vector<int const> const filtered = filter(v, isOdd); copy(filtered.begin(), filtered.end(), ostream_iterator<int const>(cout, " ")); } However on compiling this code, I get the following error messages that I am unable to understand and hence get rid of: /usr/include/c++/4.3/ext/new_allocator.h: In instantiation of ‘__gnu_cxx::new_allocator<const int>’: /usr/include/c++/4.3/bits/allocator.h:84: instantiated from ‘std::allocator<const int>’ /usr/include/c++/4.3/bits/stl_vector.h:75: instantiated from ‘std::_Vector_base<const int, std::allocator<const int> >’ /usr/include/c++/4.3/bits/stl_vector.h:176: instantiated from ‘std::vector<const int, std::allocator<const int> >’ Filter.cpp:29: instantiated from here /usr/include/c++/4.3/ext/new_allocator.h:82: error: ‘const _Tp* __gnu_cxx::new_allocator<_Tp>::address(const _Tp&) const [with _Tp = const int]’ cannot be overloaded /usr/include/c++/4.3/ext/new_allocator.h:79: error: with ‘_Tp* __gnu_cxx::new_allocator<_Tp>::address(_Tp&) const [with _Tp = const int]’ Filter.cpp: In function ‘Container<A, Allocator> filter(const Container<A, Allocator>&, const Predicate&) [with Container = std::vector, Predicate = bool ()(int), Allocator = std::allocator<const int>, A = const int]’: Filter.cpp:30: instantiated from here Filter.cpp:23: error: passing ‘const std::vector<const int, std::allocator<const int> >’ as ‘this’ argument of ‘__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> > std::vector<_Tp, _Alloc>::erase(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, __gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >) [with _Tp = const int, _Alloc = std::allocator<const int>]’ discards qualifiers /usr/include/c++/4.3/bits/stl_algo.h: In function ‘_FIter std::remove_if(_FIter, _FIter, _Predicate) [with _FIter = __gnu_cxx::__normal_iterator<const int*, std::vector<const int, std::allocator<const int> > >, _Predicate = bool (*)(int)]’: Filter.cpp:23: instantiated from ‘Container<A, Allocator> filter(const Container<A, Allocator>&, const Predicate&) [with Container = std::vector, Predicate = bool ()(int), Allocator = std::allocator<const int>, A = const int]’ Filter.cpp:30: instantiated from here /usr/include/c++/4.3/bits/stl_algo.h:821: error: assignment of read-only location ‘__result.__gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = const int*, _Container = std::vector<const int, std::allocator<const int> >]()’ /usr/include/c++/4.3/ext/new_allocator.h: In member function ‘void __gnu_cxx::new_allocator<_Tp>::deallocate(_Tp*, size_t) [with _Tp = const int]’: /usr/include/c++/4.3/bits/stl_vector.h:150: instantiated from ‘void std::_Vector_base<_Tp, _Alloc>::_M_deallocate(_Tp*, size_t) [with _Tp = const int, _Alloc = std::allocator<const int>]’ /usr/include/c++/4.3/bits/stl_vector.h:136: instantiated from ‘std::_Vector_base<_Tp, _Alloc>::~_Vector_base() [with _Tp = const int, _Alloc = std::allocator<const int>]’ /usr/include/c++/4.3/bits/stl_vector.h:286: instantiated from ‘std::vector<_Tp, _Alloc>::vector(_InputIterator, _InputIterator, const _Alloc&) [with _InputIterator = const int*, _Tp = const int, _Alloc = std::allocator<const int>]’ Filter.cpp:29: instantiated from here /usr/include/c++/4.3/ext/new_allocator.h:98: error: invalid conversion from ‘const void*’ to ‘void*’ /usr/include/c++/4.3/ext/new_allocator.h:98: error: initializing argument 1 of ‘void operator delete(void*)’ /usr/include/c++/4.3/bits/stl_algobase.h: In function ‘_OI std::__copy_move_a(_II, _II, _OI) [with bool _IsMove = false, _II = const int*, _OI = const int*]’: /usr/include/c++/4.3/bits/stl_algobase.h:435: instantiated from ‘_OI std::__copy_move_a2(_II, _II, _OI) [with bool _IsMove = false, _II = __gnu_cxx::__normal_iterator<const int*, std::vector<const int, std::allocator<const int> > >, _OI = __gnu_cxx::__normal_iterator<const int*, std::vector<const int, std::allocator<const int> > >]’ /usr/include/c++/4.3/bits/stl_algobase.h:466: instantiated from ‘_OI std::copy(_II, _II, _OI) [with _II = __gnu_cxx::__normal_iterator<const int*, std::vector<const int, std::allocator<const int> > >, _OI = __gnu_cxx::__normal_iterator<const int*, std::vector<const int, std::allocator<const int> > >]’ /usr/include/c++/4.3/bits/vector.tcc:136: instantiated from ‘__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> > std::vector<_Tp, _Alloc>::erase(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, __gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >) [with _Tp = const int, _Alloc = std::allocator<const int>]’ Filter.cpp:23: instantiated from ‘Container<A, Allocator> filter(const Container<A, Allocator>&, const Predicate&) [with Container = std::vector, Predicate = bool ()(int), Allocator = std::allocator<const int>, A = const int]’ Filter.cpp:30: instantiated from here /usr/include/c++/4.3/bits/stl_algobase.h:396: error: no matching function for call to ‘std::__copy_move<false, true, std::random_access_iterator_tag>::__copy_m(const int*&, const int*&, const int*&)’ Please tell me what I am doing wrong here and what is the correct way to achieve the kind of higher order polymorphism I want. Thanks.

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cannot delete from doubly linked list using visual studios in C

- by Jesus Sanchez

hello I am currently doing an assignment that is supposed to read in a file, use the information, and then print out another file. all using doubly linked list. Currently i am trying to just read in the file into a doubly linked list, print it out onto the screen and a file, and finally delete the list and close the program. The program works fine as long as I don't call the dlist_distroy function which is supposed to delete the string. as soon as I do it the program starts running and then a window pops up saying "Windows has triggered a breakpoint in tempfilter.exe. This may be due to a corruption of the heap, which indicates a bug in tempfilter.exe or any of the DLLs it has loaded. This may also be due to the user pressing F12 while tempfilter.exe has focus. The output window may have more diagnostic information." I have revised the destroy and remove functions and cant understand the problem. my program is the following main.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "Dlist.h" #include "dlistdata.h" /**************************************************************************************************/ int main ( int argc, char *argv[] ) { FILE *ifp, *ofp; int hour, min; Dlist *list; DlistElmt *current=NULL, *element; float temp; list = (Dlist *)malloc(sizeof(list)); element = (DlistElmt *)malloc(sizeof(element)); if ( argc != 3 ) /* argc should be 3 for correct execution */ { /* We print argv[0] assuming it is the program name */ /* TODO: This is wrong, it should be: usage: %s inputfile outputfile */ printf( "usage: %s filename", argv[0] ); } else { // We assume argv[1] is a filename to open ifp = fopen( argv[1], "r" ); if (ifp == 0 ){ printf("Could not open file\n"); } else{ ofp = fopen(argv[2], "w"); dlist_init(list);//, (destroy)(hour, min, temp)); while (fscanf(ifp, "%d:%d %f ", &hour, &min, &temp) == 3) { current=list->tail; if(dlist_size(list)==0){ dlist_ins_prev(list, current, hour, min, temp); } else{ dlist_ins_next(list, current, hour, min, temp); } } current = list->head; while(current != NULL){ if(current==list->head){ current=current->next; } else if((current->temp > (current->prev->temp +5)) || (current->temp < (current->prev->temp -5))){ dlist_remove(list, current); current=current->next; } else current=current->next; } current = list->head; while(current != NULL){ printf("%d:%d %2.1lf\n" ,current->time, current->time2, current->temp ); fprintf(ofp, "%d:%d %2.1lf\n", current->time, current->time2, current->temp ); current = current->next; } //dlist_destroy(list); //} fclose(ifp); fclose(ofp); } } getchar(); } dlistdata.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "dlistdata.h" /**************************************************************************************************/ void dlist_init(Dlist *list){ list->size = 0; list->head = NULL; list->tail = NULL; return; } void dlist_destroy(Dlist *list){ while (dlist_size(list) > 0){ dlist_remove(list, list->head); } memset(list, 0, sizeof(Dlist)); return; } int dlist_ins_next(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0) { list->head = new_element; list->head->prev = NULL; list->head->next = NULL; list->tail = new_element; } else { new_element->next = element->next; new_element->prev = element; if(element->next == NULL) list->tail = new_element; else element->next->prev = new_element; element->next = new_element; } list->size++; return 0; } int dlist_ins_prev(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0){ list->head = new_element; list->head->prev = NULL; list->head->next=NULL; list->tail = new_element; } else{ new_element->next = element; new_element->prev = element->prev; if(element->prev ==NULL) list->head = new_element; else element->prev->next = new_element; element->prev = new_element; } list->size++; return 0; } int dlist_remove(Dlist *list, DlistElmt *element){//, int time, int time2, float temp){ if (element == NULL || dlist_size(list) == 0) return -1; if (element == list->head) { list->head = element->next; if (list->head == NULL) list->tail = NULL; else element->next->prev = NULL; } else{ element->prev->next = element->next; if (element->next = NULL) list->tail = element->prev; else element->next->prev = element->prev; } free(element); list->size--; return 0; }

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need prefuse graph edges like arrows

- by merve

Hello, I did my homework and searched both google for a sample and a topic that is answered before on stackoverflow. But nothing has been found. My problem is ordinary edges who does not have a view like arrows. Here is what i do to hope there is forward arrows from target to destination: LabelRenderer nameLabel = new LabelRenderer("name"); nameLabel.setRoundedCorner(8, 8); DefaultRendererFactory rendererFactory = new DefaultRendererFactory(nameLabel); EdgeRenderer edgeRenderer; edgeRenderer = new EdgeRenderer(prefuse.Constants.EDGE_TYPE_LINE, prefuse.Constants.EDGE_ARROW_FORWARD); rendererFactory.setDefaultEdgeRenderer(edgeRenderer); vis.setRendererFactory(rendererFactory); Here is what i see about colour of edges, hoping these must not be transparent: int[] palette = new int[]{ColorLib.rgb(255, 180, 180), ColorLib.rgb(190, 190, 255)}; DataColorAction fill = new DataColorAction("socialnet.nodes", "gender", Constants.NOMINAL, VisualItem.FILLCOLOR, palette); ColorAction text = new ColorAction("socialnet.nodes", VisualItem.TEXTCOLOR, ColorLib.gray(0)); ColorAction edges = new ColorAction("socialnet.edges", VisualItem.STROKECOLOR, ColorLib.gray(200)); ColorAction arrow = new ColorAction("socialnet.edges", VisualItem.FILLCOLOR, ColorLib.gray(200)); ActionList colour = new ActionList(); colour.add(fill); colour.add(text); colour.add(edges); colour.add(arrow); vis.putAction("colour", colour); Thus, i wonder where am i wrong? Why my edges do not seem like arrows? Thanks for any idea. For more detail, i want to paste all of the code: /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package prefusedeneme; import javax.swing.JFrame; import prefuse.data.*; import prefuse.data.io.*; import prefuse.Display; import prefuse.Visualization; import prefuse.render.*; import prefuse.util.*; import prefuse.action.assignment.*; import prefuse.Constants; import prefuse.visual.*; import prefuse.action.*; import prefuse.activity.*; import prefuse.action.layout.graph.*; import prefuse.controls.*; import prefuse.data.expression.Predicate; import prefuse.data.expression.parser.ExpressionParser; public class SocialNetworkVis { public static void main(String argv[]) { // 1. Load the data Graph graph = null; /* graph will contain the core data */ try { graph = new GraphMLReader().readGraph("socialnet.xml"); /* load the data from an XML file */ } catch (DataIOException e) { e.printStackTrace(); System.err.println("Error loading graph. Exiting..."); System.exit(1); } // 2. prepare the visualization Visualization vis = new Visualization(); /* vis is the main object that will run the visualization */ vis.add("socialnet", graph); /* add our data to the visualization */ // 3. setup the renderers and the render factory // labels for name LabelRenderer nameLabel = new LabelRenderer("name"); nameLabel.setRoundedCorner(8, 8); /* nameLabel decribes how to draw the data elements labeled as "name" */ // create the render factory DefaultRendererFactory rendererFactory = new DefaultRendererFactory(nameLabel); EdgeRenderer edgeRenderer; edgeRenderer = new EdgeRenderer(prefuse.Constants.EDGE_TYPE_LINE, prefuse.Constants.EDGE_ARROW_FORWARD); rendererFactory.setDefaultEdgeRenderer(edgeRenderer); vis.setRendererFactory(rendererFactory); // 4. process the actions // colour palette for nominal data type int[] palette = new int[]{ColorLib.rgb(255, 180, 180), ColorLib.rgb(190, 190, 255)}; /* ColorLib.rgb converts the colour values to integers */ // map data to colours in the palette DataColorAction fill = new DataColorAction("socialnet.nodes", "gender", Constants.NOMINAL, VisualItem.FILLCOLOR, palette); /* fill describes what colour to draw the graph based on a portion of the data */ // node text ColorAction text = new ColorAction("socialnet.nodes", VisualItem.TEXTCOLOR, ColorLib.gray(0)); /* text describes what colour to draw the text */ // edge ColorAction edges = new ColorAction("socialnet.edges", VisualItem.STROKECOLOR, ColorLib.gray(200)); ColorAction arrow = new ColorAction("socialnet.edges", VisualItem.FILLCOLOR, ColorLib.gray(200)); /* edge describes what colour to draw the edges */ // combine the colour assignments into an action list ActionList colour = new ActionList(); colour.add(fill); colour.add(text); colour.add(edges); colour.add(arrow); vis.putAction("colour", colour); /* add the colour actions to the visualization */ // create a separate action list for the layout ActionList layout = new ActionList(Activity.INFINITY); layout.add(new ForceDirectedLayout("socialnet")); /* use a force-directed graph layout with default parameters */ layout.add(new RepaintAction()); /* repaint after each movement of the graph nodes */ vis.putAction("layout", layout); /* add the laout actions to the visualization */ // 5. add interactive controls for visualization Display display = new Display(vis); display.setSize(700, 700); display.pan(350, 350); // pan to the middle display.addControlListener(new DragControl()); /* allow items to be dragged around */ display.addControlListener(new PanControl()); /* allow the display to be panned (moved left/right, up/down) (left-drag)*/ display.addControlListener(new ZoomControl()); /* allow the display to be zoomed (right-drag) */ // 6. launch the visualizer in a JFrame JFrame frame = new JFrame("prefuse tutorial: socialnet"); /* frame is the main window */ frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(display); /* add the display (which holds the visualization) to the window */ frame.pack(); frame.setVisible(true); /* start the visualization working */ vis.run("colour"); vis.run("layout"); } }

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C++ Deck and Card Class Error with bad alloc

- by user3702164

Just started learn to code in school. Our assignment requires us to create a card game with card,deck and hand class. I am having troubles with it now and i keep getting exception: std::bad_alloc at memory location. Here are my codes right now CardType h: #ifndef cardType_h #define cardType_h #include <string> using namespace std; class cardType{ public: void print(); int getValue() const; string getSymbol() const; string getSpecial() const; string getSuit() const; int checkSpecial(int gscore) const; cardType(); cardType(string suit,int value); private: int value; string special; string symbol; string suit; }; #endif CardType cpp: #include "cardType.h" #include <iostream> #include <string> using namespace std; void cardType::print() { cout << getSymbol() << " of " << getSuit() << ", having the value of " << getValue() << "."<< endl <<"This card's special is " << getSpecial() << endl; } int cardType::getValue() const { return value; } string cardType::getSymbol() const { return symbol; } string cardType::getSpecial() const { return special; } string cardType::getSuit() const { return suit; } cardType::cardType(){ value=0; symbol="?"; special='?'; suit='?'; } cardType::cardType(string s, int v){ suit = s; value = v; switch(v){ case 1: // Ace cards have a value of 1 and have no special type symbol="Ace"; special="None"; break; case 2: // 2 cards have a value of 2 and have no special type symbol="2"; special="None"; break; case 3: symbol="3"; // 3 cards have a value of 3 and have no special type special="None"; break; case 4: symbol="4"; // 4 cards have a value of 0 and have a special type "Reverse" which reverses the flow of the game special="Reverse"; value=0; break; case 5: symbol="5"; // 5 cards have a value of 5 and have no special type special="None"; break; case 6: symbol="6"; // 6 cards have a value of 6 and have no special type special="None"; break; case 7: symbol="7"; // 7 cards have a value of 7 and have no special type special="None"; break; case 8: symbol="8"; // 8 cards have a value of 8 and have no special type special="None"; break; case 9: symbol="9"; // 9 cards have a value of 0 and have a special type "Pass" which does not add any value to the game and lets the player skip his turn. special="Pass"; value=0; break; case 10: symbol="10"; // 10 cards have a value of 10 and have a special type "subtract" which instead of adding the 10 value to the total game it is subtracted instead. special="Subtract"; value=10; break; case 11: // Jack cards have a value of 10 and have no special type symbol="Jack"; special="None"; value=10; break; case 12: // Queens cards have a value of 10 and have no special type symbol="Queen"; special="None"; value=10; break; case 13: symbol="King"; // King cards have a value of 0 and have a special type "NinetyNine" which changes the total game score to 99 reguardless what number it was previously special="NinetyNine"; value=0; break; } } int cardType::checkSpecial(int gscore) const{ if(special=="Pass"){ return gscore; } if(special=="Reverse"){ return gscore; } if(special=="Subtract"){ return gscore - value; } if(special=="NinetyNine"){ return 99; } else{ return gscore + value; } } DeckType h: #ifndef deckType_h #define deckType_h #include "cardType.h" #include <string> using namespace std; class deckType { public: void shuffle(); cardType dealCard(); deckType(); private: cardType *deck; int current; }; #endif DeckType cpp: #include <iostream> #include "deckType.h" using namespace std; deckType::deckType() { int index = 0; int current=0; deck = new cardType[52]; string suit[] = {"Hearts","Diamonds","Clubs","Spades"}; int value[] = {1,2,3,4,5,6,7,8,9,10,11,12,13}; for ( int i = 0; i <= 3; i++ ) { for ( int j = 1; j <= 13; j++ ) { deck[index] = cardType(suit[i],value[j]); index++; } } } cardType deckType::dealCard() { return deck[current]; current++; } Main cpp : #include "deckType.h" #include <iostream> using namespace std; int main() { deckType gamedeck; cout << "1" <<endl; cardType currentCard; cout << "2" <<endl; currentCard = gamedeck.dealCard(); cout << "3" <<endl; return 0; } I keep getting bad_alloc at the currentCard = gamedeck.dealCard(); I really do not know what i have done wrong.

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Need help with copy constructor for very basic implementation of singly linked lists

- by Jesus

Last week, we created a program that manages sets of strings, using classes and vectors. I was able to complete this 100%. This week, we have to replace the vector we used to store strings in our class with simple singly linked lists. The function basically allows users to declare sets of strings that are empty, and sets with only one element. In the main file, there is a vector whose elements are a struct that contain setName and strSet (class). HERE IS MY PROBLEM: It deals with the copy constructor of the class. When I remove/comment out the copy constructor, I can declare as many empty or single sets as I want, and output their values without a problem. But I know I will obviously need the copy constructor for when I implement the rest of the program. When I leave the copy constructor in, I can declare one set, either single or empty, and output its value. But if I declare a 2nd set, and i try to output either of the first two sets, i get a Segmentation Fault. Moreover, if i try to declare more then 2 sets, I get a Segmentation Fault. Any help would be appreciated!! Here is my code for a very basic implementation of everything: Here is the setcalc.cpp: (main file) #include <iostream> #include <cctype> #include <cstring> #include <string> #include "help.h" #include "strset2.h" using namespace std; // Declares of structure to hold all the sets defined struct setsOfStr { string nameOfSet; strSet stringSet; }; // Checks if the set name inputted is unique bool isSetNameUnique( vector<setsOfStr> strSetArr, string setName) { for(unsigned int i = 0; i < strSetArr.size(); i++) { if( strSetArr[i].nameOfSet == setName ) { return false; } } return true; } int main(int argc, char *argv[]) { char commandChoice; // Declares a vector with our declared structure as the type vector<setsOfStr> strSetVec; string setName; string singleEle; // Sets a loop that will constantly ask for a command until 'q' is typed while (1) { // declaring a set to be empty if(commandChoice == 'd') { cin >> setName; // Check that the set name inputted is unique if (isSetNameUnique(strSetVec, setName) == true) { strSet emptyStrSet; setsOfStr set1; set1.nameOfSet = setName; set1.stringSet = emptyStrSet; strSetVec.push_back(set1); } else { cerr << "ERROR: Re-declaration of set '" << setName << "'\n"; } } // declaring a set to be a singleton else if(commandChoice == 's') { cin >> setName; cin >> singleEle; // Check that the set name inputted is unique if (isSetNameUnique(strSetVec, setName) == true) { strSet singleStrSet(singleEle); setsOfStr set2; set2.nameOfSet = setName; set2.stringSet = singleStrSet; strSetVec.push_back(set2); } else { cerr << "ERROR: Re-declaration of set '" << setName << "'\n"; } } // using the output function else if(commandChoice == 'o') { cin >> setName; if(isSetNameUnique(strSetVec, setName) == false) { // loop through until the set name is matched and call output on its strSet for(unsigned int k = 0; k < strSetVec.size(); k++) { if( strSetVec[k].nameOfSet == setName ) { (strSetVec[k].stringSet).output(); } } } else { cerr << "ERROR: No such set '" << setName << "'\n"; } } // quitting else if(commandChoice == 'q') { break; } else { cerr << "ERROR: Ignoring bad command: '" << commandChoice << "'\n"; } } return 0; } Here is the strSet2.h: #ifndef _STRSET_ #define _STRSET_ #include <iostream> #include <vector> #include <string> struct node { std::string s1; node * next; }; class strSet { private: node * first; public: strSet (); // Create empty set strSet (std::string s); // Create singleton set strSet (const strSet &copy); // Copy constructor // will implement destructor later void output() const; strSet& operator = (const strSet& rtSide); // Assignment }; // End of strSet class #endif // _STRSET_ And here is the strSet2.cpp (implementation of class) #include <iostream> #include <vector> #include <string> #include "strset2.h" using namespace std; strSet::strSet() { first = NULL; } strSet::strSet(string s) { node *temp; temp = new node; temp->s1 = s; temp->next = NULL; first = temp; } strSet::strSet(const strSet& copy) { cout << "copy-cst\n"; node *n = copy.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } void strSet::output() const { if(first == NULL) { cout << "Empty set\n"; } else { node *temp; temp = first; while(1) { cout << temp->s1 << endl; if(temp->next == NULL) break; temp = temp->next; } } } strSet& strSet::operator = (const strSet& rtSide) { first = rtSide.first; return *this; }

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C++ function not found during compilation

- by forthewinwin

For a homework assignment: I'm supposed to create randomized alphabetial keys, print them to a file, and then hash each of them into a hash table using the function "goodHash", found in my below code. When I try to run the below code, it says my "goodHash" "identifier isn't found". What's wrong with my code? #include <iostream> #include <vector> #include <cstdlib> #include "math.h" #include <fstream> #include <time.h> using namespace std; // "makeKey" function to create an alphabetical key // based on 8 randomized numbers 0 - 25. string makeKey() { int k; string key = ""; for (k = 0; k < 8; k++) { int keyNumber = (rand() % 25); if (keyNumber == 0) key.append("A"); if (keyNumber == 1) key.append("B"); if (keyNumber == 2) key.append("C"); if (keyNumber == 3) key.append("D"); if (keyNumber == 4) key.append("E"); if (keyNumber == 5) key.append("F"); if (keyNumber == 6) key.append("G"); if (keyNumber == 7) key.append("H"); if (keyNumber == 8) key.append("I"); if (keyNumber == 9) key.append("J"); if (keyNumber == 10) key.append("K"); if (keyNumber == 11) key.append("L"); if (keyNumber == 12) key.append("M"); if (keyNumber == 13) key.append("N"); if (keyNumber == 14) key.append("O"); if (keyNumber == 15) key.append("P"); if (keyNumber == 16) key.append("Q"); if (keyNumber == 17) key.append("R"); if (keyNumber == 18) key.append("S"); if (keyNumber == 19) key.append("T"); if (keyNumber == 20) key.append("U"); if (keyNumber == 21) key.append("V"); if (keyNumber == 22) key.append("W"); if (keyNumber == 23) key.append("X"); if (keyNumber == 24) key.append("Y"); if (keyNumber == 25) key.append("Z"); } return key; } // "makeFile" function to produce the desired text file. // Note this only works as intended if you include the ".txt" extension, // and that a file of the same name doesn't already exist. void makeFile(string fileName, int n) { ofstream ourFile; ourFile.open(fileName); int k; // For use in below loop to compare with n. int l; // For use in the loop inside the below loop. string keyToPassTogoodHash = ""; for (k = 1; k <= n; k++) { for (l = 0; l < 8; l++) { // For-loop to write to the file ONE key ourFile << makeKey()[l]; keyToPassTogoodHash += (makeKey()[l]); } ourFile << " " << k << "\n";// Writes two spaces and the data value goodHash(keyToPassTogoodHash); // I think this has to do with the problem makeKey(); // Call again to make a new key. } } // Primary function to create our desired file! void mainFunction(string fileName, int n) { makeKey(); makeFile(fileName, n); } // Hash Table for Part 2 struct Node { int key; string value; Node* next; }; const int hashTableSize = 10; Node* hashTable[hashTableSize]; // "goodHash" function for Part 2 void goodHash(string key) { int x = 0; int y; int keyConvertedToNumber = 0; // For-loop to produce a numeric value based on the alphabetic key, // which is then hashed into hashTable using the hash function // declared below the loop (hashFunction). for (y = 0; y < 8; y++) { if (key[y] == 'A' || 'B' || 'C') x = 0; if (key[y] == 'D' || 'E' || 'F') x = 1; if (key[y] == 'G' || 'H' || 'I') x = 2; if (key[y] == 'J' || 'K' || 'L') x = 3; if (key[y] == 'M' || 'N' || 'O') x = 4; if (key[y] == 'P' || 'Q' || 'R') x = 5; if (key[y] == 'S' || 'T') x = 6; if (key[y] == 'U' || 'V') x = 7; if (key[y] == 'W' || 'X') x = 8; if (key[y] == 'Y' || 'Z') x = 9; keyConvertedToNumber = x + keyConvertedToNumber; } int hashFunction = keyConvertedToNumber % hashTableSize; Node *temp; temp = new Node; temp->value = key; temp->next = hashTable[hashFunction]; hashTable[hashFunction] = temp; } // First two lines are for Part 1, to call the functions key to Part 1. int main() { srand ( time(NULL) ); // To make sure our randomization works. mainFunction("sandwich.txt", 5); // To test program cin.get(); return 0; } I realize my code is cumbersome in some sections, but I'm a noob at C++ and don't know much to do it better. I'm guessing another way I could do it is to AFTER writing the alphabetical keys to the file, read them from the file and hash each key as I do that, but I wouldn't know how to go about coding that.

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Erroneous/Incorrect C2248 error using Visual Studio 2010

- by Dylan Bourque

I'm seeing what I believe to be an erroneous/incorrect compiler error using the Visual Studio 2010 compiler. I'm in the process of up-porting our codebase from Visual Studio 2005 and I ran across a construct that was building correctly before but now generates a C2248 compiler error. Obviously, the code snippet below has been generic-ized, but it is a compilable example of the scenario. The ObjectPtr<T> C++ template comes from our codebase and is the source of the error in question. What appears to be happening is that the compiler is generating a call to the copy constructor for ObjectPtr<T> when it shouldn't (see my comment block in the SomeContainer::Foo() method below). For this code construct, there is a public cast operator for SomeUsefulData * on ObjectPtr<SomeUsefulData> but it is not being chosen inside the true expression if the ?: operator. Instead, I get the two errors in the block quote below. Based on my knowledge of C++, this code should compile. Has anyone else seen this behavior? If not, can someone point me to a clarification of the compiler resolution rules that would explain why it's attempting to generate a copy of the object in this case? Thanks in advance, Dylan Bourque Visual Studio build output: c:\projects\objectptrtest\objectptrtest.cpp(177): error C2248: 'ObjectPtr::ObjectPtr' : cannot access private member declared in class 'ObjectPtr' with [ T=SomeUsefulData ] c:\projects\objectptrtest\objectptrtest.cpp(25) : see declaration of 'ObjectPtr::ObjectPtr' with [ T=SomeUsefulData ] c:\projects\objectptrtest\objectptrtest.cpp(177): error C2248: 'ObjectPtr::ObjectPtr' : cannot access private member declared in class 'ObjectPtr' with [ T=SomeUsefulData ] c:\projects\objectptrtest\objectptrtest.cpp(25) : see declaration of 'ObjectPtr::ObjectPtr' with [ T=SomeUsefulData ] Below is a minimal, compilable example of the scenario: #include <stdio.h> #include <tchar.h> template<class T> class ObjectPtr { public: ObjectPtr<T> (T* pObj = NULL, bool bShared = false) : m_pObject(pObj), m_bObjectShared(bShared) {} ~ObjectPtr<T> () { Detach(); } private: // private, unimplemented copy constructor and assignment operator // to guarantee that ObjectPtr<T> objects are not copied ObjectPtr<T> (const ObjectPtr<T>&); ObjectPtr<T>& operator = (const ObjectPtr<T>&); public: T * GetObject () { return m_pObject; } const T * GetObject () const { return m_pObject; } bool HasObject () const { return (GetObject()!=NULL); } bool IsObjectShared () const { return m_bObjectShared; } void ObjectShared (bool bShared) { m_bObjectShared = bShared; } bool IsNull () const { return !HasObject(); } void Attach (T* pObj, bool bShared = false) { Detach(); if (pObj != NULL) { m_pObject = pObj; m_bObjectShared = bShared; } } void Detach (T** ppObject = NULL) { if (ppObject != NULL) { *ppObject = m_pObject; m_pObject = NULL; m_bObjectShared = false; } else { if (HasObject()) { if (!IsObjectShared()) delete m_pObject; m_pObject = NULL; m_bObjectShared = false; } } } void Detach (bool bDeleteIfNotShared) { if (HasObject()) { if (bDeleteIfNotShared && !IsObjectShared()) delete m_pObject; m_pObject = NULL; m_bObjectShared = false; } } bool IsEqualTo (const T * pOther) const { return (GetObject() == pOther); } public: T * operator -> () { ASSERT(HasObject()); return m_pObject; } const T * operator -> () const { ASSERT(HasObject()); return m_pObject; } T & operator * () { ASSERT(HasObject()); return *m_pObject; } const T & operator * () const { ASSERT(HasObject()); return (const C &)(*m_pObject); } operator T * () { return m_pObject; } operator const T * () const { return m_pObject; } operator bool() const { return (m_pObject!=NULL); } ObjectPtr<T>& operator = (T * pObj) { Attach(pObj, false); return *this; } bool operator == (const T * pOther) const { return IsEqualTo(pOther); } bool operator == (T * pOther) const { return IsEqualTo(pOther); } bool operator != (const T * pOther) const { return !IsEqualTo(pOther); } bool operator != (T * pOther) const { return !IsEqualTo(pOther); } bool operator == (const ObjectPtr<T>& other) const { return IsEqualTo(other.GetObject()); } bool operator != (const ObjectPtr<T>& other) const { return !IsEqualTo(other.GetObject()); } bool operator == (int pv) const { return (pv==NULL)? IsNull() : (LPVOID(m_pObject)==LPVOID(pv)); } bool operator != (int pv) const { return !(*this == pv); } private: T * m_pObject; bool m_bObjectShared; }; // Some concrete type that holds useful data class SomeUsefulData { public: SomeUsefulData () {} ~SomeUsefulData () {} }; // Some concrete type that holds a heap-allocated instance of // SomeUsefulData class SomeContainer { public: SomeContainer (SomeUsefulData* pUsefulData) { m_pData = pUsefulData; } ~SomeContainer () { // nothing to do here } public: bool EvaluateSomeCondition () { // fake condition check to give us an expression // to use in ?: operator below return true; } SomeUsefulData* Foo () { // this usage of the ?: operator generates a C2248 // error b/c it's attempting to call the copy // constructor on ObjectPtr<T> return EvaluateSomeCondition() ? m_pData : NULL; /**********[ DISCUSSION ]********** The following equivalent constructs compile w/out error and behave correctly: (1) explicit cast to SomeUsefulData* as a comiler hint return EvaluateSomeCondition() ? (SomeUsefulData *)m_pData : NULL; (2) if/else instead of ?: if (EvaluateSomeCondition()) return m_pData; else return NULL; (3) skip the condition check and return m_pData as a SomeUsefulData* directly return m_pData; **********[ END DISCUSSION ]**********/ } private: ObjectPtr<SomeUsefulData> m_pData; }; int _tmain(int argc, _TCHAR* argv[]) { return 0; }

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SQLAuthority News – TechEd India – April 12-14, 2010 Bangalore – An Unforgettable Experience – An Op

- by pinaldave

TechEd India was one of the largest Technology events in India led by Microsoft. This event was attended by more than 3,000 technology enthusiasts, making it one of the most well-organized events of the year. Though I attempted to attend almost all the technology events here, I have not seen any bigger or better event in Indian subcontinents other than this. There are 21 Technical Tracks at Tech·Ed India 2010 that span more than 745 learning opportunities. I was fortunate enough to be a part of this whole event as a speaker and a delegate, as well. TechEd India Speaker Badge and A Token of Lifetime Hotel Selection I presented three different sessions at TechEd India and was also a part of panel discussion. (The details of the sessions are given at the end of this blog post.) Due to extensive traveling, I stay away from my family occasionally. For this reason, I took my wife – Nupur and daughter Shaivi (8 months old) to the event along with me. We stayed at the same hotel where the event was organized so as to maximize my time bonding with my family and to have more time in networking with technology community, at the same time. The hotel Lalit Ashok is the largest and most luxurious venue one can find in Bangalore, located in the middle of the city. The cost of the hotel was a bit pricey, but looking at all the advantages, I had decided to ask for a booking there. Hotel Lalit Ashok Nupur Dave and Shaivi Dave Arrival Day – DAY 0 – April 11, 2010 I reached the event a day earlier, and that was one wise decision for I was able to relax a bit and go over my presentation for the next day’s course. I am a kind of person who likes to get everything ready ahead of time. I was also able to enjoy a pleasant evening with several Microsoft employees and my family friends. I even checked out the location where I would be doing presentations the next day. I was fortunate enough to meet Bijoy Singhal from Microsoft who helped me out with a few of the logistics issues that occured the day before. I was not aware of the fact that the very next day he was going to be “The Man” of the TechEd 2010 event. Vinod Kumar from Microsoft was really very kind as he talked to me regarding my subsequent session. He gave me some suggestions which were really helpful that I was able to incorporate them during my presentation. Finally, I was able to meet Abhishek Kant from Microsoft; his valuable suggestions and unlimited passion have inspired many people like me to work with the Community. Pradipta from Microsoft was also around, being extremely busy with logistics; however, in those busy times, he did find some good spare time to have a chat with me and the other Community leaders. I also met Harish Ranganathan and Sachin Rathi, both from Microsoft. It was so interesting to listen to both of them talking about SharePoint. I just have no words to express my overwhelmed spirit because of all these passionate young guys - Pradipta,Vinod, Bijoy, Harish, Sachin and Ahishek (of course!). Map of TechEd India 2010 Event Day 1 – April 12, 2010 From morning until night time, today was truly a very busy day for me. I had two presentations and one panel discussion for the day. Needless to say, I had a few meetings to attend as well. The day started with a keynote from S. Somaseger where he announced the launch of Visual Studio 2010. The keynote area was really eye-catching because of the very large, bigger-than- life uniform screen. This was truly one to show. The title music of the keynote was very interesting and it featured Bijoy Singhal as the model. It was interesting to talk to him afterwards, when we laughed at jokes together about his modeling assignment. TechEd India Keynote Opening Featuring Bijoy TechEd India 2010 Keynote – S. Somasegar Time: 11:15pm – 11:45pm Session 1: True Lies of SQL Server – SQL Myth Buster Following the excellent keynote, I had my very first session on the subject of SQL Server Myth Buster. At first, I was a bit nervous as right after the keynote, for this was my very first session and during my presentation I saw lots of Microsoft Product Team members. Well, it really went well and I had a really good discussion with attendees of the session. I felt that a well begin was half-done and my confidence was regained. Right after the session, I met a few of my Community friends and had meaningful discussions with them on many subjects. The abstract of the session is as follows: In this 30-minute demo session, I am going to briefly demonstrate few SQL Server Myths and their resolutions as I back them up with some demo. This demo presentation is a must-attend for all developers and administrators who would come to the event. This is going to be a very quick yet fun session. Pinal Presenting session at TechEd India 2010 Time: 1:00 PM – 2:00 PM Lunch with Somasegar After the session I went to see my daughter, and then I headed right away to the lunch with S. Somasegar – the keynote speaker and senior vice president of the Developer Division at Microsoft. I really thank to Abhishek who made it possible for us. Because of his efforts, all the MVPs had the opportunity to meet such a legendary person and had to talk with them on Microsoft Technology. Though Somasegar is currently holding such a high position in Microsoft, he is very polite and a real gentleman, and how I wish that everybody in industry is like him. Believe me, if you spread love and kindness, then that is what you will receive back. As soon as lunch time was over, I ran to the session hall as my second presentation was about to start. Time: 2:30pm – 3:30pm Session 2: Master Data Services in Microsoft SQL Server 2008 R2 Business Intelligence is a subject which was widely talked about at TechEd. Everybody was interested in this subject, and I did not excuse myself from this great concept as well. I consider myself fortunate as I was presenting on the subject of Master Data Services at TechEd. When I had initially learned this subject, I had a bit of confusion about the usage of this tool. Later on, I decided that I would tackle about how we all developers and DBAs are not able to understand something so simple such as this, and even worst, creating confusion about the technology. During system designing, it is very important to have a reference material or master lookup tables. Well, I talked about the same subject and presented the session keeping that as my center talk. The session went very well and I received lots of interesting questions. I got many compliments for talking about this subject on the real-life scenario. I really thank Rushabh Mehta (CEO, Solid Quality Mentors India) for his supportive suggestions that helped me prepare the slide deck, as well as the subject. Pinal Presenting session at TechEd India 2010 The abstract of the session is as follows: SQL Server Master Data Services will ship with SQL Server 2008 R2 and will improve Microsoft’s platform appeal. This session provides an in-depth demonstration of MDS features and highlights important usage scenarios. Master Data Services enables consistent decision-making process by allowing you to create, manage and propagate changes from a single master view of your business entities. Also, MDS – Master Data-hub which is a vital component, helps ensure the consistency of reporting across systems and deliver faster and more accurate results across the enterprise. We will talk about establishing the basis for a centralized approach to defining, deploying, and managing master data in the enterprise. Pinal Presenting session at TechEd India 2010 The day was still not over for me. I had ran into several friends but we were not able keep our enthusiasm under control about all the rumors saying that SQL Server 2008 R2 was about to be launched tomorrow in the keynote. I then ran to my third and final technical event for the day- a panel discussion with the top technologies of India. Time: 5:00pm – 6:00pm Panel Discussion: Harness the power of Web – SEO and Technical Blogging As I have delivered two technical sessions by this time, I was a bit tired but not less enthusiastic when I had to talk about Blog and Technology. We discussed many different topics there. I told them that the most important aspect for any blog is its content. We discussed in depth the issues with plagiarism and how to avoid it. Another topic of discussion was how we technology bloggers can create awareness in the Community about what the right kind of blogging is and what morally and technically wrong acts are. A couple of questions were raised about what type of liberty a person can have in terms of writing blogs. Well, it was generically agreed that a blog is mainly a representation of our ideas and thoughts; it should not be governed by external entities. As long as one is writing what they really want to say, but not providing incorrect information or not practicing plagiarism, a blogger should be allowed to express himself. This panel discussion was supposed to be over in an hour, but the interest of the participants was remarkable and so it was extended for 30 minutes more. Finally, we decided to bring to a close the discussion and agreed that we will continue the topic next year. TechEd India Panel Discussion on Web, Technology and SEO Surprisingly, the day was just beginning after doing all of these. By this time, I have almost met all the MVP who arrived at the event, as well as many Microsoft employees. There were lots of Community folks present, too. I decided that I would go to meet several friends from the Community and continue to communicate with me on SQLAuthority.com. I also met Abhishek Baxi and had a good talk with him regarding Win Mobile and Twitter. He also took a very quick video of me wherein I spoke in my mother’s tongue, Gujarati. It was funny that I talked in Gujarati almost all the day, but when I was talking in the interview I could not find the right Gujarati words to speak. I think we all think in English when we think about Technology, so as to address universality. After meeting them, I headed towards the Speakers’ Dinner. Time: 8:00 PM – onwards Speakers Dinner The Speakers’ dinner was indeed a wonderful opportunity for all the speakers to get together and relax. We talked so many different things, from XBOX to Hindi Movies, and from SQL to Samosas. I just could not express how much fun I had. After a long evening, when I returned tmy room and met Shaivi, I just felt instantly relaxed. Kids are really gifts from God. Today was a really long but exciting day. So many things happened in just one day: Visual Studio Lanch, lunch with Somasegar, 2 technical sessions, 1 panel discussion, community leaders meeting, speakers dinner and, last but not leas,t playing with my child! A perfect day! Day 2 – April 13, 2010 Today started with a bang with the excellent keynote by Kamal Hathi who launched SQL Server 2008 R2 in India and demonstrated the power of PowerPivot to all of us. 101 Million Rows in Excel brought lots of applause from the audience. Kamal Hathi Presenting Keynote at TechEd India 2010 The day was a bit easier one for me. I had no sessions today and no events planned. I had a few meetings planned for the second day of the event. I sat in the speaker’s lounge for half a day and met many people there. I attended nearly 9 different meetings today. The subjects of the meetings were very different. Here is a list of the topics of the Community-related meetings: SQL PASS and its involvement in India and subcontinents How to start community blogging Forums and developing aptitude towards technology Ahmedabad/Gandhinagar User Groups and their developments SharePoint and SQL Business Meeting – a client meeting Business Meeting – a potential performance tuning project Business Meeting – Solid Quality Mentors (SolidQ) And family friends Pinal Dave at TechEd India The day passed by so quickly during this meeting. In the evening, I headed to Partners Expo with friends and checked out few of the booths. I really wanted to talk about some of the products, but due to the freebies there was so much crowd that I finally decided to just take the contact details of the partner. I will now start sending them with my queries and, hopefully, I will have my questions answered. Nupur and Shaivi had also one meeting to attend; it was with our family friend Vijay Raj. Vijay is also a person who loves Technology and loves it more than anybody. I see him growing and learning every day, but still remaining as a ‘human’. I believe that if someone acquires as much knowledge as him, that person will become either a computer or cyborg. Here, Vijay is still a kind gentleman and is able to stay as our close family friend. Shaivi was really happy to play with Uncle Vijay. Pinal Dave and Vijay Raj Renuka Prasad, a Microsoft MVP, impressed me with his passion and knowledge of SQL. Every time he gives me credit for his success, I believe that he is very humble. He has way more certifications than me and has worked many more years with SQL compared to me. He is an excellent photographer as well. Most of the photos in this blog post have been taken by him. I told him if ever he wants to do a part time job, he can do the photography very well. Pinal Dave and Renuka Prasad I also met L Srividya from Microsoft, whom I was looking forward to meet. She is a bundle of knowledge that everyone would surely learn a lot from her. I was able to get a few minutes from her and well, I felt confident. She enlightened me with SQL Server BI concepts, domain management and SQL Server security and few other interesting details. I also had a wonderful time talking about SharePoint with fellow Solid Quality Mentor Joy Rathnayake. He is very passionate about SharePoint but when you talk .NET and SQL with him, he is still overwhelmingly knowledgeable. In fact, while talking to him, I figured out that the recent training he delivered was on SQL Server 2008 R2. I told him a joke that it hurts my ego as he is more popular now in SQL training and consulting than me. I am sure all of you agree that working with good people is a gift from God. I am fortunate enough to work with the best of the best Industry experts. It was a great pleasure to hang out with my Community friends – Ahswin Kini, HimaBindu Vejella, Vasudev G, Suprotim Agrawal, Dhananjay, Vikram Pendse, Mahesh Dhola, Mahesh Mitkari, Manu Zacharia, Shobhan, Hardik Shah, Ashish Mohta, Manan, Subodh Sohani and Sanjay Shetty (of course!) . (Please let me know if I have met you at the event and forgot your name to list here). Time: 8:00 PM – onwards Community Leaders Dinner After lots of meetings, I headed towards the Community Leaders dinner meeting and met almost all the folks I met in morning. The discussion was almost the same but the real good thing was that we were enjoying it. The food was really good. Nupur was invited in the event, but Shaivi could not come. When Nupur tried to enter the event, she was stopped as Shaivi did not have the pass to enter the dinner. Nupur expressed that Shaivi is only 8 months old and does not eat outside food as well and could not stay by herself at this age, but the door keeper did not agree and asked that without the entry details Shaivi could not go in, but Nupur could. Nupur called me on phone and asked me to help her out. By the time, I was outside; the organizer of the event reached to the door and happily approved Shaivi to join the party. Once in the party, Shaivi had lots of fun meeting so many people. Shaivi Dave and Abhishek Kant Dean Guida (Infragistics President and CEO) and Pinal Dave (SQLAuthority.com) Day 3 – April 14, 2010 Though, it was last day, I was very much excited today as I was about to present my very favorite session. Query Optimization and Performance Tuning is my domain expertise and I make my leaving by consulting and training the same. Today’s session was on the same subject and as an additional twist, another subject about Spatial Database was presented. I was always intrigued with Spatial Database and I have enjoyed learning about it; however, I have never thought about Spatial Indexing before it was decided that I will do this session. I really thank Solid Quality Mentor Dr. Greg Low for his assistance in helping me prepare the slide deck and also review the content. Furthermore, today was really what I call my ‘learning day’ . So far I had not attended any session in TechEd and I felt a bit down for that. Everybody spends their valuable time & money to learn something new and exciting in TechEd and I had not attended a single session at the moment thinking that it was already last day of the event. I did have a plan for the day and I attended two technical sessions before my session of spatial database. I attended 2 sessions of Vinod Kumar. Vinod is a natural storyteller and there was no doubt that his sessions would be jam-packed. People attended his sessions simply because Vinod is syhe speaker. He did not have a single time disappointed audience; he is truly a good speaker. He knows his stuff very well. I personally do not think that in India he can be compared to anyone for SQL. Time: 12:30pm-1:30pm SQL Server Query Optimization, Execution and Debugging Query Performance I really had a fun time attending this session. Vinod made this session very interactive. The entire audience really got into the presentation and started participating in the event. Vinod was presenting a small problem with Query Tuning, which any developer would have encountered and solved with their help in such a fashion that a developer feels he or she have already resolved it. In one question, I was the only one who was ready to answer and Vinod told me in a light tone that I am now allowed to answer it! The audience really found it very amusing. There was a huge crowd around Vinod after the session. Vinod – A master storyteller! Time: 3:45pm-4:45pm Data Recovery / consistency with CheckDB This session was much heavier than the earlier one, and I must say this is my most favorite session I EVER attended in India. In this TechEd I have only attended two sessions, but in my career, I have attended numerous technical sessions not only in India, but all over the world. This session had taken my breath away. One by one, Vinod took the different databases, and started to corrupt them in different ways. Each database has some unique ways to get corrupted. Once that was done, Vinod started to show the DBCC CEHCKDB and demonstrated how it can solve your problem. He finally fixed all the databases with this single tool. I do have a good knowledge of this subject, but let me honestly admit that I have learned a lot from this session. I enjoyed and cheered during this session along with other attendees. I had total satisfaction that, just like everyone, I took advantage of the event and learned something. I am now TECHnically EDucated. Pinal Dave and Vinod Kumar After two very interactive and informative SQL Sessions from Vinod Kumar, the next turn me presenting on Spatial Database and Indexing. I got once again nervous but Vinod told me to stay natural and do my presentation. Well, once I got a huge stage with a total of four projectors and a large crowd, I felt better. Time: 5:00pm-6:00pm Session 3: Developing with SQL Server Spatial and Deep Dive into Spatial Indexing Pinal Presenting session at TechEd India 2010 Pinal Presenting session at TechEd India 2010 I kicked off this session with Michael J Swart‘s beautiful spatial image. This session was the last one for the day but, to my surprise, I had more than 200+ attendees. Slowly, the rain was starting outside and I was worried that the hall would not be full; despite this, there was not a single seat available in the first five minutes of the session. Thanks to all of you for attending my presentation. I had demonstrated the map of world (and India) and quickly explained what Geographic and Geometry data types in Spatial Database are. This session had interesting story of Indexing and Comparison, as well as how different traditional indexes are from spatial indexing. Pinal Presenting session at TechEd India 2010 Due to the heavy rain during this event, the power went off for about 22 minutes (just an accident – nobodies fault). During these minutes, there were no audio, no video and no light. I continued to address the mass of 200+ people without any audio device and PowerPoint. I must thank the audience because not a single person left from the session. They all stayed in their place, some moved closure to listen to me properly. I noticed that the curiosity and eagerness to learn new things was at the peak even though it was the very last session of the TechEd. Everybody wanted get the maximum knowledge out of this whole event. I was touched by the support from audience. They listened and participated in my session even without any kinds of technology (no ppt, no mike, no AC, nothing). During these 22 minutes, I had completed my theory verbally. Pinal Presenting session at TechEd India 2010 After a while, we got the projector back online and we continued with some exciting demos. Many thanks to Microsoft people who worked energetically in background to get the backup power for project up. I had a very interesting demo wherein I overlaid Bangalore and Hyderabad on the India Map and find their aerial distance between them. After finding the aerial distance, we browsed online and found that SQL Server estimates the exact aerial distance between these two cities, as compared to the factual distance. There was a huge applause from the crowd on the subject that SQL Server takes into the count of the curvature of the earth and finds the precise distances based on details. During the process of finding the distance, I demonstrated a few examples of the indexes where I expressed how one can use those indexes to find these distances and how they can improve the performance of similar query. I also demonstrated few examples wherein we were able to see in which data type the Index is most useful. We finished the demos with a few more internal stuff. Pinal Presenting session at TechEd India 2010 Despite all issues, I was mostly satisfied with my presentation. I think it was the best session I have ever presented at any conference. There was no help from Technology for a while, but I still got lots of appreciation at the end. When we ended the session, the applause from the audience was so loud that for a moment, the rain was not audible. I was truly moved by the dedication of the Technology enthusiasts. Pinal Dave After Presenting session at TechEd India 2010 The abstract of the session is as follows: The Microsoft SQL Server 2008 delivers new spatial data types that enable you to consume, use, and extend location-based data through spatial-enabled applications. Attend this session to learn how to use spatial functionality in next version of SQL Server to build and optimize spatial queries. This session outlines the new geography data type to store geodetic spatial data and perform operations on it, use the new geometry data type to store planar spatial data and perform operations on it, take advantage of new spatial indexes for high performance queries, use the new spatial results tab to quickly and easily view spatial query results directly from within Management Studio, extend spatial data capabilities by building or integrating location-enabled applications through support for spatial standards and specifications and much more. Time: 8:00 PM – onwards Dinner by Sponsors After the lively session during the day, there was another dinner party courtesy of one of the sponsors of TechEd. All the MVPs and several Community leaders were present at the dinner. I would like to express my gratitude to Abhishek Kant for organizing this wonderful event for us. It was a blast and really relaxing in all angles. We all stayed there for a long time and talked about our sweet and unforgettable memories of the event. Pinal Dave and Bijoy Singhal It was really one wonderful event. After writing this much, I say that I have no words to express about how much I enjoyed TechEd. However, it is true that I shared with you only 1% of the total activities I have done at the event. There were so many people I have met, yet were not mentioned here although I wanted to write their names here, too . Anyway, I have learned so many things and up until now, I am not able to get over all the fun I had in this event. Pinal Dave at TechEd India 2010 The Next Days – April 15, 2010 – till today I am still not able to get my mind out of the whole experience I had at TechEd India 2010. It was like a whole Microsoft Family working together to celebrate a happy occasion. TechEd India – Truly An Unforgettable Experience! Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, SQLServer, T SQL, Technology Tagged: TechEd, TechEdIn

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Using the West Wind Web Toolkit to set up AJAX and REST Services

- by Rick Strahl

I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project. When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this: Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks. The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />   Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />   Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this: The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints. It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET jQuery AJAX Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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SQLAuthority News – TechEd India – April 12-14, 2010 Bangalore – An Unforgettable Experience – An Op

- by pinaldave

TechEd India was one of the largest Technology events in India led by Microsoft. This event was attended by more than 3,000 technology enthusiasts, making it one of the most well-organized events of the year. Though I attempted to attend almost all the technology events here, I have not seen any bigger or better event in Indian subcontinents other than this. There are 21 Technical Tracks at Tech·Ed India 2010 that span more than 745 learning opportunities. I was fortunate enough to be a part of this whole event as a speaker and a delegate, as well. TechEd India Speaker Badge and A Token of Lifetime Hotel Selection I presented three different sessions at TechEd India and was also a part of panel discussion. (The details of the sessions are given at the end of this blog post.) Due to extensive traveling, I stay away from my family occasionally. For this reason, I took my wife – Nupur and daughter Shaivi (8 months old) to the event along with me. We stayed at the same hotel where the event was organized so as to maximize my time bonding with my family and to have more time in networking with technology community, at the same time. The hotel Lalit Ashok is the largest and most luxurious venue one can find in Bangalore, located in the middle of the city. The cost of the hotel was a bit pricey, but looking at all the advantages, I had decided to ask for a booking there. Hotel Lalit Ashok Nupur Dave and Shaivi Dave Arrival Day – DAY 0 – April 11, 2010 I reached the event a day earlier, and that was one wise decision for I was able to relax a bit and go over my presentation for the next day’s course. I am a kind of person who likes to get everything ready ahead of time. I was also able to enjoy a pleasant evening with several Microsoft employees and my family friends. I even checked out the location where I would be doing presentations the next day. I was fortunate enough to meet Bijoy Singhal from Microsoft who helped me out with a few of the logistics issues that occured the day before. I was not aware of the fact that the very next day he was going to be “The Man” of the TechEd 2010 event. Vinod Kumar from Microsoft was really very kind as he talked to me regarding my subsequent session. He gave me some suggestions which were really helpful that I was able to incorporate them during my presentation. Finally, I was able to meet Abhishek Kant from Microsoft; his valuable suggestions and unlimited passion have inspired many people like me to work with the Community. Pradipta from Microsoft was also around, being extremely busy with logistics; however, in those busy times, he did find some good spare time to have a chat with me and the other Community leaders. I also met Harish Ranganathan and Sachin Rathi, both from Microsoft. It was so interesting to listen to both of them talking about SharePoint. I just have no words to express my overwhelmed spirit because of all these passionate young guys - Pradipta,Vinod, Bijoy, Harish, Sachin and Ahishek (of course!). Map of TechEd India 2010 Event Day 1 – April 12, 2010 From morning until night time, today was truly a very busy day for me. I had two presentations and one panel discussion for the day. Needless to say, I had a few meetings to attend as well. The day started with a keynote from S. Somaseger where he announced the launch of Visual Studio 2010. The keynote area was really eye-catching because of the very large, bigger-than- life uniform screen. This was truly one to show. The title music of the keynote was very interesting and it featured Bijoy Singhal as the model. It was interesting to talk to him afterwards, when we laughed at jokes together about his modeling assignment. TechEd India Keynote Opening Featuring Bijoy TechEd India 2010 Keynote – S. Somasegar Time: 11:15pm – 11:45pm Session 1: True Lies of SQL Server – SQL Myth Buster Following the excellent keynote, I had my very first session on the subject of SQL Server Myth Buster. At first, I was a bit nervous as right after the keynote, for this was my very first session and during my presentation I saw lots of Microsoft Product Team members. Well, it really went well and I had a really good discussion with attendees of the session. I felt that a well begin was half-done and my confidence was regained. Right after the session, I met a few of my Community friends and had meaningful discussions with them on many subjects. The abstract of the session is as follows: In this 30-minute demo session, I am going to briefly demonstrate few SQL Server Myths and their resolutions as I back them up with some demo. This demo presentation is a must-attend for all developers and administrators who would come to the event. This is going to be a very quick yet fun session. Pinal Presenting session at TechEd India 2010 Time: 1:00 PM – 2:00 PM Lunch with Somasegar After the session I went to see my daughter, and then I headed right away to the lunch with S. Somasegar – the keynote speaker and senior vice president of the Developer Division at Microsoft. I really thank to Abhishek who made it possible for us. Because of his efforts, all the MVPs had the opportunity to meet such a legendary person and had to talk with them on Microsoft Technology. Though Somasegar is currently holding such a high position in Microsoft, he is very polite and a real gentleman, and how I wish that everybody in industry is like him. Believe me, if you spread love and kindness, then that is what you will receive back. As soon as lunch time was over, I ran to the session hall as my second presentation was about to start. Time: 2:30pm – 3:30pm Session 2: Master Data Services in Microsoft SQL Server 2008 R2 Business Intelligence is a subject which was widely talked about at TechEd. Everybody was interested in this subject, and I did not excuse myself from this great concept as well. I consider myself fortunate as I was presenting on the subject of Master Data Services at TechEd. When I had initially learned this subject, I had a bit of confusion about the usage of this tool. Later on, I decided that I would tackle about how we all developers and DBAs are not able to understand something so simple such as this, and even worst, creating confusion about the technology. During system designing, it is very important to have a reference material or master lookup tables. Well, I talked about the same subject and presented the session keeping that as my center talk. The session went very well and I received lots of interesting questions. I got many compliments for talking about this subject on the real-life scenario. I really thank Rushabh Mehta (CEO, Solid Quality Mentors India) for his supportive suggestions that helped me prepare the slide deck, as well as the subject. Pinal Presenting session at TechEd India 2010 The abstract of the session is as follows: SQL Server Master Data Services will ship with SQL Server 2008 R2 and will improve Microsoft’s platform appeal. This session provides an in-depth demonstration of MDS features and highlights important usage scenarios. Master Data Services enables consistent decision-making process by allowing you to create, manage and propagate changes from a single master view of your business entities. Also, MDS – Master Data-hub which is a vital component, helps ensure the consistency of reporting across systems and deliver faster and more accurate results across the enterprise. We will talk about establishing the basis for a centralized approach to defining, deploying, and managing master data in the enterprise. Pinal Presenting session at TechEd India 2010 The day was still not over for me. I had ran into several friends but we were not able keep our enthusiasm under control about all the rumors saying that SQL Server 2008 R2 was about to be launched tomorrow in the keynote. I then ran to my third and final technical event for the day- a panel discussion with the top technologies of India. Time: 5:00pm – 6:00pm Panel Discussion: Harness the power of Web – SEO and Technical Blogging As I have delivered two technical sessions by this time, I was a bit tired but not less enthusiastic when I had to talk about Blog and Technology. We discussed many different topics there. I told them that the most important aspect for any blog is its content. We discussed in depth the issues with plagiarism and how to avoid it. Another topic of discussion was how we technology bloggers can create awareness in the Community about what the right kind of blogging is and what morally and technically wrong acts are. A couple of questions were raised about what type of liberty a person can have in terms of writing blogs. Well, it was generically agreed that a blog is mainly a representation of our ideas and thoughts; it should not be governed by external entities. As long as one is writing what they really want to say, but not providing incorrect information or not practicing plagiarism, a blogger should be allowed to express himself. This panel discussion was supposed to be over in an hour, but the interest of the participants was remarkable and so it was extended for 30 minutes more. Finally, we decided to bring to a close the discussion and agreed that we will continue the topic next year. TechEd India Panel Discussion on Web, Technology and SEO Surprisingly, the day was just beginning after doing all of these. By this time, I have almost met all the MVP who arrived at the event, as well as many Microsoft employees. There were lots of Community folks present, too. I decided that I would go to meet several friends from the Community and continue to communicate with me on SQLAuthority.com. I also met Abhishek Baxi and had a good talk with him regarding Win Mobile and Twitter. He also took a very quick video of me wherein I spoke in my mother’s tongue, Gujarati. It was funny that I talked in Gujarati almost all the day, but when I was talking in the interview I could not find the right Gujarati words to speak. I think we all think in English when we think about Technology, so as to address universality. After meeting them, I headed towards the Speakers’ Dinner. Time: 8:00 PM – onwards Speakers Dinner The Speakers’ dinner was indeed a wonderful opportunity for all the speakers to get together and relax. We talked so many different things, from XBOX to Hindi Movies, and from SQL to Samosas. I just could not express how much fun I had. After a long evening, when I returned tmy room and met Shaivi, I just felt instantly relaxed. Kids are really gifts from God. Today was a really long but exciting day. So many things happened in just one day: Visual Studio Lanch, lunch with Somasegar, 2 technical sessions, 1 panel discussion, community leaders meeting, speakers dinner and, last but not leas,t playing with my child! A perfect day! Day 2 – April 13, 2010 Today started with a bang with the excellent keynote by Kamal Hathi who launched SQL Server 2008 R2 in India and demonstrated the power of PowerPivot to all of us. 101 Million Rows in Excel brought lots of applause from the audience. Kamal Hathi Presenting Keynote at TechEd India 2010 The day was a bit easier one for me. I had no sessions today and no events planned. I had a few meetings planned for the second day of the event. I sat in the speaker’s lounge for half a day and met many people there. I attended nearly 9 different meetings today. The subjects of the meetings were very different. Here is a list of the topics of the Community-related meetings: SQL PASS and its involvement in India and subcontinents How to start community blogging Forums and developing aptitude towards technology Ahmedabad/Gandhinagar User Groups and their developments SharePoint and SQL Business Meeting – a client meeting Business Meeting – a potential performance tuning project Business Meeting – Solid Quality Mentors (SolidQ) And family friends Pinal Dave at TechEd India The day passed by so quickly during this meeting. In the evening, I headed to Partners Expo with friends and checked out few of the booths. I really wanted to talk about some of the products, but due to the freebies there was so much crowd that I finally decided to just take the contact details of the partner. I will now start sending them with my queries and, hopefully, I will have my questions answered. Nupur and Shaivi had also one meeting to attend; it was with our family friend Vijay Raj. Vijay is also a person who loves Technology and loves it more than anybody. I see him growing and learning every day, but still remaining as a ‘human’. I believe that if someone acquires as much knowledge as him, that person will become either a computer or cyborg. Here, Vijay is still a kind gentleman and is able to stay as our close family friend. Shaivi was really happy to play with Uncle Vijay. Pinal Dave and Vijay Raj Renuka Prasad, a Microsoft MVP, impressed me with his passion and knowledge of SQL. Every time he gives me credit for his success, I believe that he is very humble. He has way more certifications than me and has worked many more years with SQL compared to me. He is an excellent photographer as well. Most of the photos in this blog post have been taken by him. I told him if ever he wants to do a part time job, he can do the photography very well. Pinal Dave and Renuka Prasad I also met L Srividya from Microsoft, whom I was looking forward to meet. She is a bundle of knowledge that everyone would surely learn a lot from her. I was able to get a few minutes from her and well, I felt confident. She enlightened me with SQL Server BI concepts, domain management and SQL Server security and few other interesting details. I also had a wonderful time talking about SharePoint with fellow Solid Quality Mentor Joy Rathnayake. He is very passionate about SharePoint but when you talk .NET and SQL with him, he is still overwhelmingly knowledgeable. In fact, while talking to him, I figured out that the recent training he delivered was on SQL Server 2008 R2. I told him a joke that it hurts my ego as he is more popular now in SQL training and consulting than me. I am sure all of you agree that working with good people is a gift from God. I am fortunate enough to work with the best of the best Industry experts. It was a great pleasure to hang out with my Community friends – Ahswin Kini, HimaBindu Vejella, Vasudev G, Suprotim Agrawal, Dhananjay, Vikram Pendse, Mahesh Dhola, Mahesh Mitkari, Manu Zacharia, Shobhan, Hardik Shah, Ashish Mohta, Manan, Subodh Sohani and Sanjay Shetty (of course!) . (Please let me know if I have met you at the event and forgot your name to list here). Time: 8:00 PM – onwards Community Leaders Dinner After lots of meetings, I headed towards the Community Leaders dinner meeting and met almost all the folks I met in morning. The discussion was almost the same but the real good thing was that we were enjoying it. The food was really good. Nupur was invited in the event, but Shaivi could not come. When Nupur tried to enter the event, she was stopped as Shaivi did not have the pass to enter the dinner. Nupur expressed that Shaivi is only 8 months old and does not eat outside food as well and could not stay by herself at this age, but the door keeper did not agree and asked that without the entry details Shaivi could not go in, but Nupur could. Nupur called me on phone and asked me to help her out. By the time, I was outside; the organizer of the event reached to the door and happily approved Shaivi to join the party. Once in the party, Shaivi had lots of fun meeting so many people. Shaivi Dave and Abhishek Kant Dean Guida (Infragistics President and CEO) and Pinal Dave (SQLAuthority.com) Day 3 – April 14, 2010 Though, it was last day, I was very much excited today as I was about to present my very favorite session. Query Optimization and Performance Tuning is my domain expertise and I make my leaving by consulting and training the same. Today’s session was on the same subject and as an additional twist, another subject about Spatial Database was presented. I was always intrigued with Spatial Database and I have enjoyed learning about it; however, I have never thought about Spatial Indexing before it was decided that I will do this session. I really thank Solid Quality Mentor Dr. Greg Low for his assistance in helping me prepare the slide deck and also review the content. Furthermore, today was really what I call my ‘learning day’ . So far I had not attended any session in TechEd and I felt a bit down for that. Everybody spends their valuable time & money to learn something new and exciting in TechEd and I had not attended a single session at the moment thinking that it was already last day of the event. I did have a plan for the day and I attended two technical sessions before my session of spatial database. I attended 2 sessions of Vinod Kumar. Vinod is a natural storyteller and there was no doubt that his sessions would be jam-packed. People attended his sessions simply because Vinod is syhe speaker. He did not have a single time disappointed audience; he is truly a good speaker. He knows his stuff very well. I personally do not think that in India he can be compared to anyone for SQL. Time: 12:30pm-1:30pm SQL Server Query Optimization, Execution and Debugging Query Performance I really had a fun time attending this session. Vinod made this session very interactive. The entire audience really got into the presentation and started participating in the event. Vinod was presenting a small problem with Query Tuning, which any developer would have encountered and solved with their help in such a fashion that a developer feels he or she have already resolved it. In one question, I was the only one who was ready to answer and Vinod told me in a light tone that I am now allowed to answer it! The audience really found it very amusing. There was a huge crowd around Vinod after the session. Vinod – A master storyteller! Time: 3:45pm-4:45pm Data Recovery / consistency with CheckDB This session was much heavier than the earlier one, and I must say this is my most favorite session I EVER attended in India. In this TechEd I have only attended two sessions, but in my career, I have attended numerous technical sessions not only in India, but all over the world. This session had taken my breath away. One by one, Vinod took the different databases, and started to corrupt them in different ways. Each database has some unique ways to get corrupted. Once that was done, Vinod started to show the DBCC CEHCKDB and demonstrated how it can solve your problem. He finally fixed all the databases with this single tool. I do have a good knowledge of this subject, but let me honestly admit that I have learned a lot from this session. I enjoyed and cheered during this session along with other attendees. I had total satisfaction that, just like everyone, I took advantage of the event and learned something. I am now TECHnically EDucated. Pinal Dave and Vinod Kumar After two very interactive and informative SQL Sessions from Vinod Kumar, the next turn me presenting on Spatial Database and Indexing. I got once again nervous but Vinod told me to stay natural and do my presentation. Well, once I got a huge stage with a total of four projectors and a large crowd, I felt better. Time: 5:00pm-6:00pm Session 3: Developing with SQL Server Spatial and Deep Dive into Spatial Indexing Pinal Presenting session at TechEd India 2010 Pinal Presenting session at TechEd India 2010 I kicked off this session with Michael J Swart‘s beautiful spatial image. This session was the last one for the day but, to my surprise, I had more than 200+ attendees. Slowly, the rain was starting outside and I was worried that the hall would not be full; despite this, there was not a single seat available in the first five minutes of the session. Thanks to all of you for attending my presentation. I had demonstrated the map of world (and India) and quickly explained what Geographic and Geometry data types in Spatial Database are. This session had interesting story of Indexing and Comparison, as well as how different traditional indexes are from spatial indexing. Pinal Presenting session at TechEd India 2010 Due to the heavy rain during this event, the power went off for about 22 minutes (just an accident – nobodies fault). During these minutes, there were no audio, no video and no light. I continued to address the mass of 200+ people without any audio device and PowerPoint. I must thank the audience because not a single person left from the session. They all stayed in their place, some moved closure to listen to me properly. I noticed that the curiosity and eagerness to learn new things was at the peak even though it was the very last session of the TechEd. Everybody wanted get the maximum knowledge out of this whole event. I was touched by the support from audience. They listened and participated in my session even without any kinds of technology (no ppt, no mike, no AC, nothing). During these 22 minutes, I had completed my theory verbally. Pinal Presenting session at TechEd India 2010 After a while, we got the projector back online and we continued with some exciting demos. Many thanks to Microsoft people who worked energetically in background to get the backup power for project up. I had a very interesting demo wherein I overlaid Bangalore and Hyderabad on the India Map and find their aerial distance between them. After finding the aerial distance, we browsed online and found that SQL Server estimates the exact aerial distance between these two cities, as compared to the factual distance. There was a huge applause from the crowd on the subject that SQL Server takes into the count of the curvature of the earth and finds the precise distances based on details. During the process of finding the distance, I demonstrated a few examples of the indexes where I expressed how one can use those indexes to find these distances and how they can improve the performance of similar query. I also demonstrated few examples wherein we were able to see in which data type the Index is most useful. We finished the demos with a few more internal stuff. Pinal Presenting session at TechEd India 2010 Despite all issues, I was mostly satisfied with my presentation. I think it was the best session I have ever presented at any conference. There was no help from Technology for a while, but I still got lots of appreciation at the end. When we ended the session, the applause from the audience was so loud that for a moment, the rain was not audible. I was truly moved by the dedication of the Technology enthusiasts. Pinal Dave After Presenting session at TechEd India 2010 The abstract of the session is as follows: The Microsoft SQL Server 2008 delivers new spatial data types that enable you to consume, use, and extend location-based data through spatial-enabled applications. Attend this session to learn how to use spatial functionality in next version of SQL Server to build and optimize spatial queries. This session outlines the new geography data type to store geodetic spatial data and perform operations on it, use the new geometry data type to store planar spatial data and perform operations on it, take advantage of new spatial indexes for high performance queries, use the new spatial results tab to quickly and easily view spatial query results directly from within Management Studio, extend spatial data capabilities by building or integrating location-enabled applications through support for spatial standards and specifications and much more. Time: 8:00 PM – onwards Dinner by Sponsors After the lively session during the day, there was another dinner party courtesy of one of the sponsors of TechEd. All the MVPs and several Community leaders were present at the dinner. I would like to express my gratitude to Abhishek Kant for organizing this wonderful event for us. It was a blast and really relaxing in all angles. We all stayed there for a long time and talked about our sweet and unforgettable memories of the event. Pinal Dave and Bijoy Singhal It was really one wonderful event. After writing this much, I say that I have no words to express about how much I enjoyed TechEd. However, it is true that I shared with you only 1% of the total activities I have done at the event. There were so many people I have met, yet were not mentioned here although I wanted to write their names here, too . Anyway, I have learned so many things and up until now, I am not able to get over all the fun I had in this event. Pinal Dave at TechEd India 2010 The Next Days – April 15, 2010 – till today I am still not able to get my mind out of the whole experience I had at TechEd India 2010. It was like a whole Microsoft Family working together to celebrate a happy occasion. TechEd India – Truly An Unforgettable Experience! Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, MVP, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, SQLServer, T SQL, Technology Tagged: TechEd, TechEdIn

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AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

- by Varun Chatterji

Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an antipattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/startertemplate/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ngapp=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ngview attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/ExtendingHTMLwithAngularJSDirectives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ngclick=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/UnderstandingScopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial:  <div class="well" style="margin-top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng-model="model.phoneNumber" class="form-control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Message" ng-model="model.message" class="form-control" style="width: 90%" /> </td> <td style="text-align: center;"> <button class="btn btn-danger" ng-click="sendMessage();" ng-disabled="model.isAjaxInProgress" style="marginright: 5px;">Send</button> <img src="/Content/ajax-loader.gif" ng-show="model.isAjaxInProgress" /> </td> </tr> </table> </div>  <div style="margin-top: 30px;">  <div ng-show="model.allMessages.length == 0"> No messages have been sent yet! </div>  <div ng-show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr>  <tr ng-repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-danger" ng-click="delete(message.smsId);" ng-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ngclick=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-disabled directive which is added as an attribute to the buttons. The ng-repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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Windows Azure: Import/Export Hard Drives, VM ACLs, Web Sockets, Remote Debugging, Continuous Delivery, New Relic, Billing Alerts and More

- by ScottGu

Two weeks ago we released a giant set of improvements to Windows Azure, as well as a significant update of the Windows Azure SDK. This morning we released another massive set of enhancements to Windows Azure. Today’s new capabilities include: Storage: Import/Export Hard Disk Drives to your Storage Accounts HDInsight: General Availability of our Hadoop Service in the cloud Virtual Machines: New VM Gallery, ACL support for VIPs Web Sites: WebSocket and Remote Debugging Support Notification Hubs: Segmented customer push notification support with tag expressions TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services Developer Analytics: New Relic support for Web Sites + Mobile Services Service Bus: Support for partitioned queues and topics Billing: New Billing Alert Service that sends emails notifications when your bill hits a threshold you define All of these improvements are now available to use immediately (note that some features are still in preview). Below are more details about them. Storage: Import/Export Hard Disk Drives to Windows Azure I am excited to announce the preview of our new Windows Azure Import/Export Service! The Windows Azure Import/Export Service enables you to move large amounts of on-premises data into and out of your Windows Azure Storage accounts. It does this by enabling you to securely ship hard disk drives directly to our Windows Azure data centers. Once we receive the drives we’ll automatically transfer the data to or from your Windows Azure Storage account. This enables you to import or export massive amounts of data more quickly and cost effectively (and not be constrained by available network bandwidth). Encrypted Transport Our Import/Export service provides built-in support for BitLocker disk encryption – which enables you to securely encrypt data on the hard drives before you send it, and not have to worry about it being compromised even if the disk is lost/stolen in transit (since the content on the transported hard drives is completely encrypted and you are the only one who has the key to it). The drive preparation tool we are shipping today makes setting up bitlocker encryption on these hard drives easy. How to Import/Export your first Hard Drive of Data You can read our Getting Started Guide to learn more about how to begin using the import/export service. You can create import and export jobs via the Windows Azure Management Portal as well as programmatically using our Server Management APIs. It is really easy to create a new import or export job using the Windows Azure Management Portal. Simply navigate to a Windows Azure storage account, and then click the new Import/Export tab now available within it (note: if you don’t have this tab make sure to sign-up for the Import/Export preview): Then click the “Create Import Job” or “Create Export Job” commands at the bottom of it. This will launch a wizard that easily walks you through the steps required: For more comprehensive information about Import/Export, refer to Windows Azure Storage team blog. You can also send questions and comments to the [email protected] email address. We think you’ll find this new service makes it much easier to move data into and out of Windows Azure, and it will dramatically cut down the network bandwidth required when working on large data migration projects. We hope you like it. HDInsight: 100% Compatible Hadoop Service in the Cloud Last week we announced the general availability release of Windows Azure HDInsight. HDInsight is a 100% compatible Hadoop service that allows you to easily provision and manage Hadoop clusters for big data processing in Windows Azure. This release is now live in production, backed by an enterprise SLA, supported 24x7 by Microsoft Support, and is ready to use for production scenarios. HDInsight allows you to use Apache Hadoop tools, such as Pig and Hive, to process large amounts of data in Windows Azure Blob Storage. Because data is stored in Windows Azure Blob Storage, you can choose to dynamically create Hadoop clusters only when you need them, and then shut them down when they are no longer required (since you pay only for the time the Hadoop cluster instances are running this provides a super cost effective way to use them). You can create Hadoop clusters using either the Windows Azure Management Portal (see below) or using our PowerShell and Cross Platform Command line tools: The import/export hard drive support that came out today is a perfect companion service to use with HDInsight – the combination allows you to easily ingest, process and optionally export a limitless amount of data. We’ve also integrated HDInsight with our Business Intelligence tools, so users can leverage familiar tools like Excel in order to analyze the output of jobs. You can find out more about how to get started with HDInsight here. Virtual Machines: VM Gallery Enhancements Today’s update of Windows Azure brings with it a new Virtual Machine gallery that you can use to create new VMs in the cloud. You can launch the gallery by doing New->Compute->Virtual Machine->From Gallery within the Windows Azure Management Portal: The new Virtual Machine Gallery includes some nice enhancements that make it even easier to use: Search: You can now easily search and filter images using the search box in the top-right of the dialog. For example, simply type “SQL” and we’ll filter to show those images in the gallery that contain that substring. Category Tree-view: Each month we add more built-in VM images to the gallery. You can continue to browse these using the “All” view within the VM Gallery – or now quickly filter them using the category tree-view on the left-hand side of the dialog. For example, by selecting “Oracle” in the tree-view you can now quickly filter to see the official Oracle supplied images. MSDN and Supported checkboxes: With today’s update we are also introducing filters that makes it easy to filter out types of images that you may not be interested in. The first checkbox is MSDN: using this filter you can exclude any image that is not part of the Windows Azure benefits for MSDN subscribers (which have highly discounted pricing - you can learn more about the MSDN pricing here). The second checkbox is Supported: this filter will exclude any image that contains prerelease software, so you can feel confident that the software you choose to deploy is fully supported by Windows Azure and our partners. Sort options: We sort gallery images by what we think customers are most interested in, but sometimes you might want to sort using different views. So we’re providing some additional sort options, like “Newest,” to customize the image list for what suits you best. Pricing information: We now provide additional pricing information about images and options on how to cost effectively run them directly within the VM Gallery. The above improvements make it even easier to use the VM Gallery and quickly create launch and run Virtual Machines in the cloud. Virtual Machines: ACL Support for VIPs A few months ago we exposed the ability to configure Access Control Lists (ACLs) for Virtual Machines using Windows PowerShell cmdlets and our Service Management API. With today’s release, you can now configure VM ACLs using the Windows Azure Management Portal as well. You can now do this by clicking the new Manage ACL command in the Endpoints tab of a virtual machine instance: This will enable you to configure an ordered list of permit and deny rules to scope the traffic that can access your VM’s network endpoints. For example, if you were on a virtual network, you could limit RDP access to a Windows Azure virtual machine to only a few computers attached to your enterprise. Or if you weren’t on a virtual network you could alternatively limit traffic from public IPs that can access your workloads: Here is the default behaviors for ACLs in Windows Azure: By default (i.e. no rules specified), all traffic is permitted. When using only Permit rules, all other traffic is denied. When using only Deny rules, all other traffic is permitted. When there is a combination of Permit and Deny rules, all other traffic is denied. Lastly, remember that configuring endpoints does not automatically configure them within the VM if it also has firewall rules enabled at the OS level. So if you create an endpoint using the Windows Azure Management Portal, Windows PowerShell, or REST API, be sure to also configure your guest VM firewall appropriately as well. Web Sites: Web Sockets Support With today’s release you can now use Web Sockets with Windows Azure Web Sites. This feature enables you to easily integrate real-time communication scenarios within your web based applications, and is available at no extra charge (it even works with the free tier). Higher level programming libraries like SignalR and socket.io are also now supported with it. You can enable Web Sockets support on a web site by navigating to the Configure tab of a Web Site, and by toggling Web Sockets support to “on”: Once Web Sockets is enabled you can start to integrate some really cool scenarios into your web applications. Check out the new SignalR documentation hub on www.asp.net to learn more about some of the awesome scenarios you can do with it. Web Sites: Remote Debugging Support The Windows Azure SDK 2.2 we released two weeks ago introduced remote debugging support for Windows Azure Cloud Services. With today’s Windows Azure release we are extending this remote debugging support to also work with Windows Azure Web Sites. With live, remote debugging support inside of Visual Studio, you are able to have more visibility than ever before into how your code is operating live in Windows Azure. It is now super easy to attach the debugger and quickly see what is going on with your application in the cloud. Remote Debugging of a Windows Azure Web Site using VS 2013 Enabling the remote debugging of a Windows Azure Web Site using VS 2013 is really easy. Start by opening up your web application’s project within Visual Studio. Then navigate to the “Server Explorer” tab within Visual Studio, and click on the deployed web-site you want to debug that is running within Windows Azure using the Windows Azure->Web Sites node in the Server Explorer. Then right-click and choose the “Attach Debugger” option on it: When you do this Visual Studio will remotely attach the debugger to the Web Site running within Windows Azure. The debugger will then stop the web site’s execution when it hits any break points that you have set within your web application’s project inside Visual Studio. For example, below I set a breakpoint on the “ViewBag.Message” assignment statement within the HomeController of the standard ASP.NET MVC project template. When I hit refresh on the “About” page of the web site within the browser, the breakpoint was triggered and I am now able to debug the app remotely using Visual Studio: Note above how we can debug variables (including autos/watchlist/etc), as well as use the Immediate and Command Windows. In the debug session above I used the Immediate Window to explore some of the request object state, as well as to dynamically change the ViewBag.Message property. When we click the the “Continue” button (or press F5) the app will continue execution and the Web Site will render the content back to the browser. This makes it super easy to debug web apps remotely. Tips for Better Debugging To get the best experience while debugging, we recommend publishing your site using the Debug configuration within Visual Studio’s Web Publish dialog. This will ensure that debug symbol information is uploaded to the Web Site which will enable a richer debug experience within Visual Studio. You can find this option on the Web Publish dialog on the Settings tab: When you ultimately deploy/run the application in production we recommend using the “Release” configuration setting – the release configuration is memory optimized and will provide the best production performance. To learn more about diagnosing and debugging Windows Azure Web Sites read our new Troubleshooting Windows Azure Web Sites in Visual Studio guide. Notification Hubs: Segmented Push Notification support with tag expressions In August we announced the General Availability of Windows Azure Notification Hubs - a powerful Mobile Push Notifications service that makes it easy to send high volume push notifications with low latency from any mobile app back-end. Notification hubs can be used with any mobile app back-end (including ones built using our Mobile Services capability) and can also be used with back-ends that run in the cloud as well as on-premises. Beginning with the initial release, Notification Hubs allowed developers to send personalized push notifications to both individual users as well as groups of users by interest, by associating their devices with tags representing the logical target of the notification. For example, by registering all devices of customers interested in a favorite MLB team with a corresponding tag, it is possible to broadcast one message to millions of Boston Red Sox fans and another message to millions of St. Louis Cardinals fans with a single API call respectively. New support for using tag expressions to enable advanced customer segmentation With today’s release we are adding support for even more advanced customer targeting. You can now identify customers that you want to send push notifications to by defining rich tag expressions. With tag expressions, you can now not only broadcast notifications to Boston Red Sox fans, but take that segmenting a step farther and reach more granular segments. This opens up a variety of scenarios, for example: Offers based on multiple preferences—e.g. send a game day vegetarian special to users tagged as both a Boston Red Sox fan AND a vegetarian Push content to multiple segments in a single message—e.g. rain delay information only to users who are tagged as either a Boston Red Sox fan OR a St. Louis Cardinal fan Avoid presenting subsets of a segment with irrelevant content—e.g. season ticket availability reminder to users who are tagged as a Boston Red Sox fan but NOT also a season ticket holder To illustrate with code, consider a restaurant chain app that sends an offer related to a Red Sox vs Cardinals game for users in Boston. Devices can be tagged by your app with location tags (e.g. “Loc:Boston”) and interest tags (e.g. “Follows:RedSox”, “Follows:Cardinals”), and then a notification can be sent by your back-end to “(Follows:RedSox || Follows:Cardinals) && Loc:Boston” in order to deliver an offer to all devices in Boston that follow either the RedSox or the Cardinals. This can be done directly in your server backend send logic using the code below: var notification = new WindowsNotification(messagePayload); hub.SendNotificationAsync(notification, "(Follows:RedSox || Follows:Cardinals) && Loc:Boston"); In your expressions you can use all Boolean operators: AND (&&), OR (||), and NOT (!). Some other cool use cases for tag expressions that are now supported include: Social: To “all my group except me” - group:id && !user:id Events: Touchdown event is sent to everybody following either team or any of the players involved in the action: Followteam:A || Followteam:B || followplayer:1 || followplayer:2 … Hours: Send notifications at specific times. E.g. Tag devices with time zone and when it is 12pm in Seattle send to: GMT8 && follows:thaifood Versions and platforms: Send a reminder to people still using your first version for Android - version:1.0 && platform:Android For help on getting started with Notification Hubs, visit the Notification Hub documentation center. Then download the latest NuGet package (or use the Notification Hubs REST APIs directly) to start sending push notifications using tag expressions. They are really powerful and enable a bunch of great new scenarios. TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services With today’s Windows Azure release we are making it really easy to enable continuous delivery support with Windows Azure and Team Foundation Services. Team Foundation Services is a cloud based offering from Microsoft that provides integrated source control (with both TFS and Git support), build server, test execution, collaboration tools, and agile planning support. It makes it really easy to setup a team project (complete with automated builds and test runners) in the cloud, and it has really rich integration with Visual Studio. With today’s Windows Azure release it is now really easy to enable continuous delivery support with both TFS and Git based repositories hosted using Team Foundation Services. This enables a workflow where when code is checked in, built successfully on an automated build server, and all tests pass on it – I can automatically have the app deployed on Windows Azure with zero manual intervention or work required. The below screen-shots demonstrate how to quickly setup a continuous delivery workflow to Windows Azure with a Git-based ASP.NET MVC project hosted using Team Foundation Services. Enabling Continuous Delivery to Windows Azure with Team Foundation Services The project I’m going to enable continuous delivery with is a simple ASP.NET MVC project whose source code I’m hosting using Team Foundation Services. I did this by creating a “SimpleContinuousDeploymentTest” repository there using Git – and then used the new built-in Git tooling support within Visual Studio 2013 to push the source code to it. Below is a screen-shot of the Git repository hosted within Team Foundation Services: I can access the repository within Visual Studio 2013 and easily make commits with it (as well as branch, merge and do other tasks). Using VS 2013 I can also setup automated builds to take place in the cloud using Team Foundation Services every time someone checks in code to the repository: The cool thing about this is that I don’t have to buy or rent my own build server – Team Foundation Services automatically maintains its own build server farm and can automatically queue up a build for me (for free) every time someone checks in code using the above settings. This build server (and automated testing) support now works with both TFS and Git based source control repositories. Connecting a Team Foundation Services project to Windows Azure Once I have a source repository hosted in Team Foundation Services with Automated Builds and Testing set up, I can then go even further and set it up so that it will be automatically deployed to Windows Azure when a source code commit is made to the repository (assuming the Build + Tests pass). Enabling this is now really easy. To set this up with a Windows Azure Web Site simply use the New->Compute->Web Site->Custom Create command inside the Windows Azure Management Portal. This will create a dialog like below. I gave the web site a name and then made sure the “Publish from source control” checkbox was selected: When we click next we’ll be prompted for the location of the source repository. We’ll select “Team Foundation Services”: Once we do this we’ll be prompted for our Team Foundation Services account that our source repository is hosted under (in this case my TFS account is “scottguthrie”): When we click the “Authorize Now” button we’ll be prompted to give Windows Azure permissions to connect to the Team Foundation Services account. Once we do this we’ll be prompted to pick the source repository we want to connect to. Starting with today’s Windows Azure release you can now connect to both TFS and Git based source repositories. This new support allows me to connect to the “SimpleContinuousDeploymentTest” respository we created earlier: Clicking the finish button will then create the Web Site with the continuous delivery hooks setup with Team Foundation Services. Now every time someone pushes source control to the repository in Team Foundation Services, it will kick off an automated build, run all of the unit tests in the solution , and if they pass the app will be automatically deployed to our Web Site in Windows Azure. You can monitor the history and status of these automated deployments using the Deployments tab within the Web Site: This enables a really slick continuous delivery workflow, and enables you to build and deploy apps in a really nice way. Developer Analytics: New Relic support for Web Sites + Mobile Services With today’s Windows Azure release we are making it really easy to enable Developer Analytics and Monitoring support with both Windows Azure Web Site and Windows Azure Mobile Services. We are partnering with New Relic, who provide a great dev analytics and app performance monitoring offering, to enable this - and we have updated the Windows Azure Management Portal to make it really easy to configure. Enabling New Relic with a Windows Azure Web Site Enabling New Relic support with a Windows Azure Web Site is now really easy. Simply navigate to the Configure tab of a Web Site and scroll down to the “developer analytics” section that is now within it: Clicking the “add-on” button will display some additional UI. If you don’t already have a New Relic subscription, you can click the “view windows azure store” button to obtain a subscription (note: New Relic has a perpetually free tier so you can enable it even without paying anything): Clicking the “view windows azure store” button will launch the integrated Windows Azure Store experience we have within the Windows Azure Management Portal. You can use this to browse from a variety of great add-on services – including New Relic: Select “New Relic” within the dialog above, then click the next button, and you’ll be able to choose which type of New Relic subscription you wish to purchase. For this demo we’ll simply select the “Free Standard Version” – which does not cost anything and can be used forever: Once we’ve signed-up for our New Relic subscription and added it to our Windows Azure account, we can go back to the Web Site’s configuration tab and choose to use the New Relic add-on with our Windows Azure Web Site. We can do this by simply selecting it from the “add-on” dropdown (it is automatically populated within it once we have a New Relic subscription in our account): Clicking the “Save” button will then cause the Windows Azure Management Portal to automatically populate all of the needed New Relic configuration settings to our Web Site: Deploying the New Relic Agent as part of a Web Site The final step to enable developer analytics using New Relic is to add the New Relic runtime agent to our web app. We can do this within Visual Studio by right-clicking on our web project and selecting the “Manage NuGet Packages” context menu: This will bring up the NuGet package manager. You can search for “New Relic” within it to find the New Relic agent. Note that there is both a 32-bit and 64-bit edition of it – make sure to install the version that matches how your Web Site is running within Windows Azure (note: you can configure your Web Site to run in either 32-bit or 64-bit mode using the Web Site’s “Configuration” tab within the Windows Azure Management Portal): Once we install the NuGet package we are all set to go. We’ll simply re-publish the web site again to Windows Azure and New Relic will now automatically start monitoring the application Monitoring a Web Site using New Relic Now that the application has developer analytics support with New Relic enabled, we can launch the New Relic monitoring portal to start monitoring the health of it. We can do this by clicking on the “Add Ons” tab in the left-hand side of the Windows Azure Management Portal. Then select the New Relic add-on we signed-up for within it. The Windows Azure Management Portal will provide some default information about the add-on when we do this. Clicking the “Manage” button in the tray at the bottom will launch a new browser tab and single-sign us into the New Relic monitoring portal associated with our account: When we do this a new browser tab will launch with the New Relic admin tool loaded within it: We can now see insights into how our app is performing – without having to have written a single line of monitoring code. The New Relic service provides a ton of great built-in monitoring features allowing us to quickly see: Performance times (including browser rendering speed) for the overall site and individual pages. You can optionally set alert thresholds to trigger if the speed does not meet a threshold you specify. Information about where in the world your customers are hitting the site from (and how performance varies by region) Details on the latency performance of external services your web apps are using (for example: SQL, Storage, Twitter, etc) Error information including call stack details for exceptions that have occurred at runtime SQL Server profiling information – including which queries executed against your database and what their performance was And a whole bunch more… The cool thing about New Relic is that you don’t need to write monitoring code within your application to get all of the above reports (plus a lot more). The New Relic agent automatically enables the CLR profiler within applications and automatically captures the information necessary to identify these. This makes it super easy to get started and immediately have a rich developer analytics view for your solutions with very little effort. If you haven’t tried New Relic out yet with Windows Azure I recommend you do so – I think you’ll find it helps you build even better cloud applications. Following the above steps will help you get started and deliver you a really good application monitoring solution in only minutes. Service Bus: Support for partitioned queues and topics With today’s release, we are enabling support within Service Bus for partitioned queues and topics. Enabling partitioning enables you to achieve a higher message throughput and better availability from your queues and topics. Higher message throughput is achieved by implementing multiple message brokers for each partitioned queue and topic. The multiple messaging stores will also provide higher availability. You can create a partitioned queue or topic by simply checking the Enable Partitioning option in the custom create wizard for a Queue or Topic: Read this article to learn more about partitioned queues and topics and how to take advantage of them today. Billing: New Billing Alert Service Today’s Windows Azure update enables a new Billing Alert Service Preview that enables you to get proactive email notifications when your Windows Azure bill goes above a certain monetary threshold that you configure. This makes it easier to manage your bill and avoid potential surprises at the end of the month. With the Billing Alert Service Preview, you can now create email alerts to monitor and manage your monetary credits or your current bill total. To set up an alert first sign-up for the free Billing Alert Service Preview. Then visit the account management page, click on a subscription you have setup, and then navigate to the new Alerts tab that is available: The alerts tab allows you to setup email alerts that will be sent automatically once a certain threshold is hit. For example, by clicking the “add alert” button above I can setup a rule to send myself email anytime my Windows Azure bill goes above $100 for the month: The Billing Alert Service will evolve to support additional aspects of your bill as well as support multiple forms of alerts such as SMS. Try out the new Billing Alert Service Preview today and give us feedback. Summary Today’s Windows Azure release enables a ton of great new scenarios, and makes building applications hosted in the cloud even easier. If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using all of the above features today. Then visit the Windows Azure Developer Center to learn more about how to build apps with it. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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JAVA image transfer problem

- by user579098

Hi, I have a school assignment, to send a jpg image,split it into groups of 100 bytes, corrupt it, use a CRC check to locate the errors and re-transmit until it eventually is built back into its original form. It's practically ready, however when I check out the new images, they appear with errors.. I would really appreciate if someone could look at my code below and maybe locate this logical mistake as I can't understand what the problem is because everything looks ok :S For the file with all the data needed including photos and error patterns one could download it from this link:http://rapidshare.com/#!download|932tl2|443122762|Data.zip|739 Thanks in advance, Stefan p.s dont forget to change the paths in the code for the image and error files package networks; import java.io.*; // for file reader import java.util.zip.CRC32; // CRC32 IEEE (Ethernet) public class Main { /** * Reads a whole file into an array of bytes. * @param file The file in question. * @return Array of bytes containing file data. * @throws IOException Message contains why it failed. */ public static byte[] readFileArray(File file) throws IOException { InputStream is = new FileInputStream(file); byte[] data=new byte[(int)file.length()]; is.read(data); is.close(); return data; } /** * Writes (or overwrites if exists) a file with data from an array of bytes. * @param file The file in question. * @param data Array of bytes containing the new file data. * @throws IOException Message contains why it failed. */ public static void writeFileArray(File file, byte[] data) throws IOException { OutputStream os = new FileOutputStream(file,false); os.write(data); os.close(); } /** * Converts a long value to an array of bytes. * @param data The target variable. * @return Byte array conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static byte[] toByta(long data) { return new byte[] { (byte)((data >> 56) & 0xff), (byte)((data >> 48) & 0xff), (byte)((data >> 40) & 0xff), (byte)((data >> 32) & 0xff), (byte)((data >> 24) & 0xff), (byte)((data >> 16) & 0xff), (byte)((data >> 8) & 0xff), (byte)((data >> 0) & 0xff), }; } /** * Converts a an array of bytes to long value. * @param data The target variable. * @return Long value conversion of data. * @see http://www.daniweb.com/code/snippet216874.html */ public static long toLong(byte[] data) { if (data == null || data.length != 8) return 0x0; return (long)( // (Below) convert to longs before shift because digits // are lost with ints beyond the 32-bit limit (long)(0xff & data[0]) << 56 | (long)(0xff & data[1]) << 48 | (long)(0xff & data[2]) << 40 | (long)(0xff & data[3]) << 32 | (long)(0xff & data[4]) << 24 | (long)(0xff & data[5]) << 16 | (long)(0xff & data[6]) << 8 | (long)(0xff & data[7]) << 0 ); } public static byte[] nextNoise(){ byte[] result=new byte[100]; // copy a frame's worth of data (or remaining data if it is less than frame length) int read=Math.min(err_data.length-err_pstn, 100); System.arraycopy(err_data, err_pstn, result, 0, read); // if read data is less than frame length, reset position and add remaining data if(read<100){ err_pstn=100-read; System.arraycopy(err_data, 0, result, read, err_pstn); }else // otherwise, increase position err_pstn+=100; // return noise segment return result; } /** * Given some original data, it is purposefully corrupted according to a * second data array (which is read from a file). In pseudocode: * corrupt = original xor corruptor * @param data The original data. * @return The new (corrupted) data. */ public static byte[] corruptData(byte[] data){ // get the next noise sequence byte[] noise = nextNoise(); // finally, xor data with noise and return result for(int i=0; i<100; i++)data[i]^=noise[i]; return data; } /** * Given an array of data, a packet is created. In pseudocode: * frame = corrupt(data) + crc(data) * @param data The original frame data. * @return The resulting frame data. */ public static byte[] buildFrame(byte[] data){ // pack = [data]+crc32([data]) byte[] hash = new byte[8]; // calculate crc32 of data and copy it to byte array CRC32 crc = new CRC32(); crc.update(data); hash=toByta(crc.getValue()); // create a byte array holding the final packet byte[] pack = new byte[data.length+hash.length]; // create the corrupted data byte[] crpt = new byte[data.length]; crpt = corruptData(data); // copy corrupted data into pack System.arraycopy(crpt, 0, pack, 0, crpt.length); // copy hash into pack System.arraycopy(hash, 0, pack, data.length, hash.length); // return pack return pack; } /** * Verifies frame contents. * @param frame The frame data (data+crc32). * @return True if frame is valid, false otherwise. */ public static boolean verifyFrame(byte[] frame){ // allocate hash and data variables byte[] hash=new byte[8]; byte[] data=new byte[frame.length-hash.length]; // read frame into hash and data variables System.arraycopy(frame, frame.length-hash.length, hash, 0, hash.length); System.arraycopy(frame, 0, data, 0, frame.length-hash.length); // get crc32 of data CRC32 crc = new CRC32(); crc.update(data); // compare crc32 of data with crc32 of frame return crc.getValue()==toLong(hash); } /** * Transfers a file through a channel in frames and reconstructs it into a new file. * @param jpg_file File name of target file to transfer. * @param err_file The channel noise file used to simulate corruption. * @param out_file The name of the newly-created file. * @throws IOException */ public static void transferFile(String jpg_file, String err_file, String out_file) throws IOException { // read file data into global variables jpg_data = readFileArray(new File(jpg_file)); err_data = readFileArray(new File(err_file)); err_pstn = 0; // variable that will hold the final (transfered) data byte[] out_data = new byte[jpg_data.length]; // holds the current frame data byte[] frame_orig = new byte[100]; byte[] frame_sent = new byte[100]; // send file in chunks (frames) of 100 bytes for(int i=0; i<Math.ceil(jpg_data.length/100); i++){ // copy jpg data into frame and init first-time switch System.arraycopy(jpg_data, i*100, frame_orig, 0, 100); boolean not_first=false; System.out.print("Packet #"+i+": "); // repeat getting same frame until frame crc matches with frame content do { if(not_first)System.out.print("F"); frame_sent=buildFrame(frame_orig); not_first=true; }while(!verifyFrame(frame_sent)); // usually, you'd constrain this by time to prevent infinite loops (in // case the channel is so wacked up it doesn't get a single packet right) // copy frame to image file System.out.println("S"); System.arraycopy(frame_sent, 0, out_data, i*100, 100); } System.out.println("\nDone."); writeFileArray(new File(out_file),out_data); } // global variables for file data and pointer public static byte[] jpg_data; public static byte[] err_data; public static int err_pstn=0; public static void main(String[] args) throws IOException { // list of jpg files String[] jpg_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo1.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo2.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo3.jpg", "C:\\Users\\Stefan\\Desktop\\Data\\Images\\photo4.jpg" }; // list of error patterns String[] err_file={ "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 1.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 2.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 3.DAT", "C:\\Users\\Stefan\\Desktop\\Data\\Error Pattern\\Error Pattern 4.DAT" }; // loop through all jpg/channel combinations and run tests for(int x=0; x<jpg_file.length; x++){ for(int y=0; y<err_file.length; y++){ System.out.println("Transfering photo"+(x+1)+".jpg using Pattern "+(y+1)+"..."); transferFile(jpg_file[x],err_file[y],jpg_file[x].replace("photo","CH#"+y+"_photo")); } } } }

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using ResultSet.Previous method not working in Java using .mdb file OBDC

- by jsonnie

Hello, I'm currently having an issue with my open result set not working how I believe it should. The only function that is currently working is the next() method, nothing else will work. If the project is placed into a debug mode you can follow through actionperformed event on the button it hits the previous() method and jumps over the remaining code in the method. If someone could point me in the right direction it would be truly appreciated. FORM CODE: import java.sql.; import javax.swing.; public class DataNavigator extends javax.swing.JFrame { public DataInterface db = null; public Statement s = null; public Connection con = null; public PreparedStatement stmt = null; public ResultSet rs = null; /** Creates new form DataNavigator */ public DataNavigator() { initComponents(); try { db = new DataInterface("jdbc:odbc:CMPS422"); con = db.getConnection(); stmt = con.prepareStatement("SELECT * FROM Products"); rs = stmt.executeQuery(); rs.last(); } catch (Exception e) { } } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { btnFirst = new javax.swing.JButton(); btnNext = new javax.swing.JButton(); btnLast = new javax.swing.JButton(); btnUpdate = new javax.swing.JButton(); btnInsert = new javax.swing.JButton(); btnDelete = new javax.swing.JButton(); txtPartNum = new javax.swing.JTextField(); txtDesc = new javax.swing.JTextField(); txtQty = new javax.swing.JTextField(); txtPrice = new javax.swing.JTextField(); jLabel1 = new javax.swing.JLabel(); jLabel2 = new javax.swing.JLabel(); jLabel3 = new javax.swing.JLabel(); jLabel4 = new javax.swing.JLabel(); btnPrev = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); setTitle("Assignment 3 Data Navigator"); addWindowListener(new java.awt.event.WindowAdapter() { public void windowOpened(java.awt.event.WindowEvent evt) { formWindowOpened(evt); } }); btnFirst.setText("First"); btnFirst.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btnFirstActionPerformed(evt); } }); btnNext.setText("Next"); btnNext.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btnNextActionPerformed(evt); } }); btnLast.setText("Last"); btnLast.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btnLastActionPerformed(evt); } }); btnUpdate.setText("Update"); btnInsert.setText("Insert"); btnDelete.setText("Delete"); jLabel1.setText("Part Number:"); jLabel2.setText("Description:"); jLabel3.setText("Quantity:"); jLabel4.setText("Price:"); btnPrev.setText("Prev"); btnPrev.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnPrevMouseClicked(evt); } }); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addContainerGap() .addComponent(btnFirst) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(2, 2, 2) .addComponent(btnPrev) .addGap(4, 4, 4) .addComponent(btnNext) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnLast)) .addComponent(jLabel1) .addComponent(jLabel2) .addComponent(jLabel3) .addComponent(jLabel4)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) .addComponent(txtPartNum) .addGroup(layout.createSequentialGroup() .addComponent(btnUpdate) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnInsert) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnDelete)) .addComponent(txtDesc) .addComponent(txtQty) .addComponent(txtPrice)) .addContainerGap(71, Short.MAX_VALUE)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addContainerGap() .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(btnFirst) .addComponent(btnNext) .addComponent(btnLast) .addComponent(btnUpdate) .addComponent(btnInsert) .addComponent(btnDelete) .addComponent(btnPrev)) .addGap(66, 66, 66) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addComponent(jLabel1) .addComponent(txtPartNum, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addComponent(txtDesc, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addComponent(jLabel2)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addComponent(txtQty, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addComponent(jLabel3)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addComponent(txtPrice, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addComponent(jLabel4)) .addContainerGap(102, Short.MAX_VALUE)) ); pack(); }// </editor-fold> private void formWindowOpened(java.awt.event.WindowEvent evt) { try { this.txtPartNum.setText(rs.getString("Partnum")); this.txtDesc.setText(rs.getString("Description")); this.txtPrice.setText(rs.getString("Price")); this.txtQty.setText(rs.getString("Quantity")); } catch (SQLException e) { } } private void btnNextActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: try { System.out.println(rs.getCursorName()); rs.next(); rs.moveToCurrentRow(); System.out.println(rs.getCursorName()); this.txtPartNum.setText(rs.getString("Partnum")); this.txtDesc.setText(rs.getString("Description")); this.txtPrice.setText(rs.getString("Price")); this.txtQty.setText(rs.getString("Quantity")); System.out.println(rs.getRow()); } catch (Exception e) { } } private void btnLastActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: try { rs.last(); this.txtPartNum.setText(rs.getString("Partnum")); this.txtDesc.setText(rs.getString("Description")); this.txtPrice.setText(rs.getString("Price")); this.txtQty.setText(rs.getString("Quantity")); } catch (Exception e) { } } private void btnFirstActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: try { rs.first(); this.txtPartNum.setText(rs.getString("Partnum")); this.txtDesc.setText(rs.getString("Description")); this.txtPrice.setText(rs.getString("Price")); this.txtQty.setText(rs.getString("Quantity")); } catch (Exception e) { } } private void btnPrevMouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: try { int i; i = rs.getRow(); if (i > 0) { rs.previous(); System.out.println(rs.getRow()); this.txtPartNum.setText(rs.getString("Partnum")); this.txtDesc.setText(rs.getString("Description")); this.txtPrice.setText(rs.getString("Price")); this.txtQty.setText(rs.getString("Quantity")); } else { System.out.println("FALSE"); } } catch (Exception e) { } } /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new DataNavigator().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JButton btnDelete; private javax.swing.JButton btnFirst; private javax.swing.JButton btnInsert; private javax.swing.JButton btnLast; private javax.swing.JButton btnNext; private javax.swing.JButton btnPrev; private javax.swing.JButton btnUpdate; private javax.swing.JLabel jLabel1; private javax.swing.JLabel jLabel2; private javax.swing.JLabel jLabel3; private javax.swing.JLabel jLabel4; private javax.swing.JTextField txtDesc; private javax.swing.JTextField txtPartNum; private javax.swing.JTextField txtPrice; private javax.swing.JTextField txtQty; // End of variables declaration } CLASS OBJECT CODE: import java.sql.*; import javax.swing.JOptionPane; public class DataInterface { private static DataInterface dbint = null; private static Connection conn = null; // connection object. private static ResultSet rset = null; public DataInterface(String ODBCDSN) { try { // See if the driver is present. Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); // Open connection to database. conn = DriverManager.getConnection(ODBCDSN); JOptionPane.showMessageDialog(null, "Database successfully opened"); } catch (Exception e) { JOptionPane.showMessageDialog(null, e.toString()); } } public Connection getConnection() { return conn; } public static DataInterface getInstance() { return dbint; } public static ResultSet getResultSet() { return rset; } public PreparedStatement setStatement(String a) throws SQLException{ PreparedStatement stmt = conn.prepareStatement(a); return stmt; }

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How do I improve my performance with this singly linked list struct within my program?

- by Jesus

Hey guys, I have a program that does operations of sets of strings. We have to implement functions such as addition and subtraction of two sets of strings. We are suppose to get it down to the point where performance if of O(N+M), where N,M are sets of strings. Right now, I believe my performance is at O(N*M), since I for each element of N, I go through every element of M. I'm particularly focused on getting the subtraction to the proper performance, as if I can get that down to proper performance, I believe I can carry that knowledge over to the rest of things I have to implement. The '-' operator is suppose to work like this, for example. Declare set1 to be an empty set. Declare set2 to be a set with { a b c } elements Declare set3 to be a set with ( b c d } elements set1 = set2 - set3 And now set1 is suppose to equal { a }. So basically, just remove any element from set3, that is also in set2. For the addition implementation (overloaded '+' operator), I also do the sorting of the strings (since we have to). All the functions work right now btw. So I was wondering if anyone could a) Confirm that currently I'm doing O(N*M) performance b) Give me some ideas/implementations on how to improve the performance to O(N+M) Note: I cannot add any member variables or functions to the class strSet or to the node structure. The implementation of the main program isn't very important, but I will post the code for my class definition and the implementation of the member functions: strSet2.h (Implementation of my class and struct) // Class to implement sets of strings // Implements operators for union, intersection, subtraction, // etc. for sets of strings // V1.1 15 Feb 2011 Added guard (#ifndef), deleted using namespace RCH #ifndef _STRSET_ #define _STRSET_ #include <iostream> #include <vector> #include <string> // Deleted: using namespace std; 15 Feb 2011 RCH struct node { std::string s1; node * next; }; class strSet { private: node * first; public: strSet (); // Create empty set strSet (std::string s); // Create singleton set strSet (const strSet &copy); // Copy constructor ~strSet (); // Destructor int SIZE() const; bool isMember (std::string s) const; strSet operator + (const strSet& rtSide); // Union strSet operator - (const strSet& rtSide); // Set subtraction strSet& operator = (const strSet& rtSide); // Assignment }; // End of strSet class #endif // _STRSET_ strSet2.cpp (implementation of member functions) #include <iostream> #include <vector> #include <string> #include "strset2.h" using namespace std; strSet::strSet() { first = NULL; } strSet::strSet(string s) { node *temp; temp = new node; temp->s1 = s; temp->next = NULL; first = temp; } strSet::strSet(const strSet& copy) { if(copy.first == NULL) { first = NULL; } else { node *n = copy.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } strSet::~strSet() { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } } int strSet::SIZE() const { int size = 0; node *temp = first; while(temp!=NULL) { size++; temp=temp->next; } return size; } bool strSet::isMember(string s) const { node *temp = first; while(temp != NULL) { if(temp->s1 == s) { return true; } temp = temp->next; } return false; } strSet strSet::operator + (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string newEle = temp->s1; if(!isMember(newEle)) { if(newSet.first==NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first = newNode; } else if(newSet.SIZE() == 1) { if(newEle < newSet.first->s1) { node *tempNext = newSet.first; node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = tempNext; newSet.first = newNode; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first->next = newNode; } } else { node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if(newEle < curr->s1) { if(prev == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; newSet.first = newNode; break; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; prev->next = newNode; break; } } if(curr->next == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; curr->next = newNode; break; } prev = curr; curr = curr->next; } } } temp = temp->next; } return newSet; } strSet strSet::operator - (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string element = temp->s1; node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if( element < curr->s1 ) break; if( curr->s1 == element ) { if( prev == NULL) { node *duplicate = curr; newSet.first = newSet.first->next; delete duplicate; break; } else { node *duplicate = curr; prev->next = curr->next; delete duplicate; break; } } prev = curr; curr = curr->next; } temp = temp->next; } return newSet; } strSet& strSet::operator = (const strSet& rtSide) { if(this != &rtSide) { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } if(rtSide.first == NULL) { first = NULL; } else { node *n = rtSide.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } return *this; }

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UITableViewCell selected subview ghosts

- by Jonathan Cohen

Hi all, I'm learning about the iPhone SDK and have an interesting exception with UITableViewCell subview management when a finger is pressed on some rows. The table is used to assign sounds to hand gestures -- swiping the phone in one of 3 directions triggers the sound to play. Selecting a row displays an action sheet with 4 options for sound assignment: left, down, right, and cancel. Sounds can be mapped to one, two, or three directions so any cell can have one of seven states: left, down, right, left and down, left and right, down and right, or left down and right. If a row is mapped to any of these seven states, a corresponding arrow or arrows are displayed within the bounds of the row as a subview. Arrows come and go as they should in a given screen and when scrolling around. However, after scrolling to a new batch of rows, only when I press my finger down on some (but not all) rows, does an arrow magically appear in the selected state background. When I lift my finger off the row, and the action sheet appears, the arrow disappears. After pressing any of the four buttons, I can't replicate this anymore. But it's really disorienting and confusing to see this arrow flash on screen because the selected row isn't assigned to anything. What haven't I thought to look into here? All my table code is pasted below and this is a screencast of the problem: http://www.screencast.com/users/JonathanGCohen/folders/Jing/media/d483fe31-05b5-4c24-ab4d-70de4ff3a0bf Am I managing my subviews wrong or is there a selected state property I'm missing? Something else? Should I have included any more information in this post to make things clearer? Thank you!! #pragma mark - #pragma mark Table - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return ([categories count] > 0) ? [categories count] : 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { if ([categories count] == 0) return 0; NSMutableString *key = [categories objectAtIndex:section]; NSMutableArray *nameSection = [categoriesSounds objectForKey:key]; return [nameSection count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSUInteger section = [indexPath section]; NSUInteger row = [indexPath row]; NSString *key = [categories objectAtIndex:section]; NSArray *nameSection = [categoriesSounds objectForKey:key]; static NSString *SectionsTableIdentifier = @"SectionsTableIdentifier"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: SectionsTableIdentifier]; NSArray *sound = [categoriesSounds objectForKey:key]; NSString *soundName = [[sound objectAtIndex: row] objectAtIndex: 0]; NSString *soundOfType = [[sound objectAtIndex: row] objectAtIndex: 1]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SectionsTableIdentifier] autorelease]; } cell.textLabel.text = [[nameSection objectAtIndex:row] objectAtIndex: 0]; NSUInteger soundSection = [[[sound objectAtIndex: row] objectAtIndex: 2] integerValue]; NSUInteger soundRow = [[[sound objectAtIndex: row] objectAtIndex: 3] integerValue]; NSUInteger leftRow = [leftOldIndexPath row]; NSUInteger leftSection = [leftOldIndexPath section]; if (soundRow == leftRow && soundSection == leftSection && leftOldIndexPath !=nil){ [selectedSoundLeftAndDown removeFromSuperview]; [selectedSoundLeftAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundLeft]; selectedSoundLeft.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundLeft]; } NSUInteger downRow = [downOldIndexPath row]; NSUInteger downSection = [downOldIndexPath section]; if (soundRow == downRow && soundSection == downSection && downOldIndexPath !=nil){ [selectedSoundLeftAndDown removeFromSuperview]; [selectedSoundDownAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundDown]; selectedSoundDown.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundDown]; } NSUInteger rightRow = [rightOldIndexPath row]; NSUInteger rightSection = [rightOldIndexPath section]; if (soundRow == rightRow && soundSection == rightSection && rightOldIndexPath !=nil){ [selectedSoundDownAndRight removeFromSuperview]; [selectedSoundLeftAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundRight]; selectedSoundRight.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundRight]; } // combos if (soundRow == leftRow && soundRow == downRow && soundSection == leftSection && soundSection == downSection){ [selectedSoundLeft removeFromSuperview]; [selectedSoundDown removeFromSuperview]; [selectedSoundLeftAndDownAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundLeftAndDown]; selectedSoundLeftAndDown.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundLeftAndDown]; } if (soundRow == leftRow && soundRow == rightRow && soundSection == leftSection && soundSection == rightSection){ [selectedSoundLeft removeFromSuperview]; [selectedSoundRight removeFromSuperview]; [selectedSoundLeftAndDownAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundLeftAndRight]; selectedSoundLeftAndRight.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundLeftAndRight]; } if (soundRow == downRow && soundRow == rightRow && soundSection == downSection && soundSection == rightSection){ [selectedSoundDown removeFromSuperview]; [selectedSoundRight removeFromSuperview]; [selectedSoundLeftAndDownAndRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundDownAndRight]; selectedSoundDownAndRight.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundDownAndRight]; } if (soundRow == leftRow && soundRow == downRow && soundRow == rightRow && soundSection == leftSection && soundSection == downSection && soundSection == rightSection){ [selectedSoundLeftAndDown removeFromSuperview]; [selectedSoundLeftAndRight removeFromSuperview]; [selectedSoundDownAndRight removeFromSuperview]; [selectedSoundLeft removeFromSuperview]; [selectedSoundDown removeFromSuperview]; [selectedSoundRight removeFromSuperview]; [cell.contentView addSubview: selectedSoundLeftAndDownAndRight]; selectedSoundLeftAndDownAndRight.frame = CGRectMake(200,8,30,30); } else { [cell.contentView sendSubviewToBack: selectedSoundLeftAndDownAndRight]; } [indexPath retain]; return cell; } - (NSMutableString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { if ([categories count] == 0) return nil; NSMutableString *key = [categories objectAtIndex:section]; if (key == UITableViewIndexSearch) return nil; return key; } - (NSMutableArray *)sectionIndexTitlesForTableView:(UITableView *)tableView { if (isSearching) return nil; return categories; } - (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath { [table reloadData]; [selectedSoundLeft removeFromSuperview]; [selectedSoundDown removeFromSuperview]; [selectedSoundRight removeFromSuperview]; [selectedSoundLeftAndDown removeFromSuperview]; [selectedSoundLeftAndRight removeFromSuperview]; [selectedSoundDownAndRight removeFromSuperview]; [selectedSoundLeftAndDownAndRight removeFromSuperview]; [search resignFirstResponder]; if (isSearching == YES && [search.text length] != 0 ){ searched = YES; } search.text = @""; isSearching = NO; [tableView reloadData]; [indexPath retain]; [indexPath retain]; return indexPath; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [table reloadData]; selectedIndexPath = indexPath; [table reloadData]; NSInteger section = [indexPath section]; NSInteger row = [indexPath row]; NSString *key = [categories objectAtIndex:section]; NSArray *sound = [categoriesSounds objectForKey:key]; NSString *soundName = [[sound objectAtIndex: row] objectAtIndex: 0]; [indexPath retain]; [indexPath retain]; NSMutableString *title = [NSMutableString stringWithString: @"Assign Gesture for "]; NSMutableString *soundFeedback = [NSMutableString stringWithString: (@"%@", soundName)]; [title appendString: soundFeedback]; UIActionSheet *action = [[UIActionSheet alloc] initWithTitle:(@"%@", title) delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle: nil otherButtonTitles:@"Left",@"Down",@"Right",nil]; action.actionSheetStyle = UIActionSheetStyleDefault; [action showInView:self.view]; [action release]; } - (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{ NSInteger section = [selectedIndexPath section]; NSInteger row = [selectedIndexPath row]; NSString *key = [categories objectAtIndex:section]; NSArray *sound = [categoriesSounds objectForKey:key]; NSString *soundName = [[sound objectAtIndex: row] objectAtIndex: 0]; NSString *soundOfType = [[sound objectAtIndex: row] objectAtIndex: 1]; NSUInteger soundSection = [[[sound objectAtIndex: row] objectAtIndex: 2] integerValue]; NSUInteger soundRow = [[[sound objectAtIndex: row] objectAtIndex: 3] integerValue]; NSLog(@"sound row is %i", soundRow); NSLog(@"sound section is row is %i", soundSection); typedef enum { kLeftButton = 0, kDownButton, kRightButton, kCancelButton } gesture; switch (buttonIndex) { //Left case kLeftButton: showLeft.text = soundName; left = [[NSBundle mainBundle] pathForResource:(@"%@", soundName) ofType:(@"%@", soundOfType)]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:left], &soundNegZ); AudioServicesPlaySystemSound (soundNegZ); [table deselectRowAtIndexPath:selectedIndexPath animated:YES]; leftIndexSection = [NSNumber numberWithInteger:section]; leftIndexRow = [NSNumber numberWithInteger:row]; NSInteger leftSection = [leftIndexSection integerValue]; NSInteger leftRow = [leftIndexRow integerValue]; NSString *leftKey = [categories objectAtIndex: leftSection]; NSArray *leftSound = [categoriesSounds objectForKey:leftKey]; NSInteger leftSoundSection = [[[leftSound objectAtIndex: leftRow] objectAtIndex: 2] integerValue]; NSInteger leftSoundRow = [[[leftSound objectAtIndex: leftRow] objectAtIndex: 3] integerValue]; leftOldIndexPath = [NSIndexPath indexPathForRow:leftSoundRow inSection:leftSoundSection]; break; //Down case kDownButton: showDown.text = soundName; down = [[NSBundle mainBundle] pathForResource:(@"%@", soundName) ofType:(@"%@", soundOfType)]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:down], &soundNegX); AudioServicesPlaySystemSound (soundNegX); [table deselectRowAtIndexPath:selectedIndexPath animated:YES]; downIndexSection = [NSNumber numberWithInteger:section]; downIndexRow = [NSNumber numberWithInteger:row]; NSInteger downSection = [downIndexSection integerValue]; NSInteger downRow = [downIndexRow integerValue]; NSString *downKey = [categories objectAtIndex: downSection]; NSArray *downSound = [categoriesSounds objectForKey:downKey]; NSInteger downSoundSection = [[[downSound objectAtIndex: downRow] objectAtIndex: 2] integerValue]; NSInteger downSoundRow = [[[downSound objectAtIndex: downRow] objectAtIndex: 3] integerValue]; downOldIndexPath = [NSIndexPath indexPathForRow:downSoundRow inSection:downSoundSection]; break; //Right case kRightButton: showRight.text = soundName; right = [[NSBundle mainBundle] pathForResource:(@"%@", soundName) ofType:(@"%@", soundOfType)]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:right], &soundPosX); AudioServicesPlaySystemSound (soundPosX); [table deselectRowAtIndexPath:selectedIndexPath animated:YES]; rightIndexSection = [NSNumber numberWithInteger:section]; rightIndexRow = [NSNumber numberWithInteger:row]; NSInteger rightSection = [rightIndexSection integerValue]; NSInteger rightRow = [rightIndexRow integerValue]; NSString *rightKey = [categories objectAtIndex: rightSection]; NSArray *rightSound = [categoriesSounds objectForKey:rightKey]; NSInteger rightSoundSection = [[[rightSound objectAtIndex: rightRow] objectAtIndex: 2] integerValue]; NSInteger rightSoundRow = [[[rightSound objectAtIndex: rightRow] objectAtIndex: 3] integerValue]; rightOldIndexPath = [NSIndexPath indexPathForRow:rightSoundRow inSection:rightSoundSection]; break; case kCancelButton: [table deselectRowAtIndexPath:selectedIndexPath animated:YES]; break; default: break; } UITableViewCell *viewCell = [table cellForRowAtIndexPath: selectedIndexPath]; NSArray *subviews = viewCell.subviews; for (UIView *cellView in subviews){ cellView.alpha = 1; } [table reloadData]; } - (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSMutableString *)title atIndex:(NSInteger)index { NSMutableString *category = [categories objectAtIndex:index]; if (category == UITableViewIndexSearch) { [tableView setContentOffset:CGPointZero animated:NO]; return NSNotFound; } else return index; }

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Followup: Python 2.6, 3 abstract base class misunderstanding

- by Aaron

I asked a question at Python 2.6, 3 abstract base class misunderstanding. My problem was that python abstract base classes didn't work quite the way I expected them to. There was some discussion in the comments about why I would want to use ABCs at all, and Alex Martelli provided an excellent answer on why my use didn't work and how to accomplish what I wanted. Here I'd like to address why one might want to use ABCs, and show my test code implementation based on Alex's answer. tl;dr: Code after the 16th paragraph. In the discussion on the original post, statements were made along the lines that you don't need ABCs in Python, and that ABCs don't do anything and are therefore not real classes; they're merely interface definitions. An abstract base class is just a tool in your tool box. It's a design tool that's been around for many years, and a programming tool that is explicitly available in many programming languages. It can be implemented manually in languages that don't provide it. An ABC is always a real class, even when it doesn't do anything but define an interface, because specifying the interface is what an ABC does. If that was all an ABC could do, that would be enough reason to have it in your toolbox, but in Python and some other languages they can do more. The basic reason to use an ABC is when you have a number of classes that all do the same thing (have the same interface) but do it differently, and you want to guarantee that that complete interface is implemented in all objects. A user of your classes can rely on the interface being completely implemented in all classes. You can maintain this guarantee manually. Over time you may succeed. Or you might forget something. Before Python had ABCs you could guarantee it semi-manually, by throwing NotImplementedError in all the base class's interface methods; you must implement these methods in derived classes. This is only a partial solution, because you can still instantiate such a base class. A more complete solution is to use ABCs as provided in Python 2.6 and above. Template methods and other wrinkles and patterns are ideas whose implementation can be made easier with full-citizen ABCs. Another idea in the comments was that Python doesn't need ABCs (understood as a class that only defines an interface) because it has multiple inheritance. The implied reference there seems to be Java and its single inheritance. In Java you "get around" single inheritance by inheriting from one or more interfaces. Java uses the word "interface" in two ways. A "Java interface" is a class with method signatures but no implementations. The methods are the interface's "interface" in the more general, non-Java sense of the word. Yes, Python has multiple inheritance, so you don't need Java-like "interfaces" (ABCs) merely to provide sets of interface methods to a class. But that's not the only reason in software development to use ABCs. Most generally, you use an ABC to specify an interface (set of methods) that will likely be implemented differently in different derived classes, yet that all derived classes must have. Additionally, there may be no sensible default implementation for the base class to provide. Finally, even an ABC with almost no interface is still useful. We use something like it when we have multiple except clauses for a try. Many exceptions have exactly the same interface, with only two differences: the exception's string value, and the actual class of the exception. In many exception clauses we use nothing about the exception except its class to decide what to do; catching one type of exception we do one thing, and another except clause catching a different exception does another thing. According to the exception module's doc page, BaseException is not intended to be derived by any user defined exceptions. If ABCs had been a first class Python concept from the beginning, it's easy to imagine BaseException being specified as an ABC. But enough of that. Here's some 2.6 code that demonstrates how to use ABCs, and how to specify a list-like ABC. Examples are run in ipython, which I like much better than the python shell for day to day work; I only wish it was available for python3. Your basic 2.6 ABC: from abc import ABCMeta, abstractmethod class Super(): __metaclass__ = ABCMeta @abstractmethod def method1(self): pass Test it (in ipython, python shell would be similar): In [2]: a = Super() --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() TypeError: Can't instantiate abstract class Super with abstract methods method1 Notice the end of the last line, where the TypeError exception tells us that method1 has not been implemented ("abstract methods method1"). That was the method designated as @abstractmethod in the preceding code. Create a subclass that inherits Super, implement method1 in the subclass and you're done. My problem, which caused me to ask the original question, was how to specify an ABC that itself defines a list interface. My naive solution was to make an ABC as above, and in the inheritance parentheses say (list). My assumption was that the class would still be abstract (can't instantiate it), and would be a list. That was wrong; inheriting from list made the class concrete, despite the abstract bits in the class definition. Alex suggested inheriting from collections.MutableSequence, which is abstract (and so doesn't make the class concrete) and list-like. I used collections.Sequence, which is also abstract but has a shorter interface and so was quicker to implement. First, Super derived from Sequence, with nothing extra: from abc import abstractmethod from collections import Sequence class Super(Sequence): pass Test it: In [6]: a = Super() --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() TypeError: Can't instantiate abstract class Super with abstract methods __getitem__, __len__ We can't instantiate it. A list-like full-citizen ABC; yea! Again, notice in the last line that TypeError tells us why we can't instantiate it: __getitem__ and __len__ are abstract methods. They come from collections.Sequence. But, I want a bunch of subclasses that all act like immutable lists (which collections.Sequence essentially is), and that have their own implementations of my added interface methods. In particular, I don't want to implement my own list code, Python already did that for me. So first, let's implement the missing Sequence methods, in terms of Python's list type, so that all subclasses act as lists (Sequences). First let's see the signatures of the missing abstract methods: In [12]: help(Sequence.__getitem__) Help on method __getitem__ in module _abcoll: __getitem__(self, index) unbound _abcoll.Sequence method (END) In [14]: help(Sequence.__len__) Help on method __len__ in module _abcoll: __len__(self) unbound _abcoll.Sequence method (END) __getitem__ takes an index, and __len__ takes nothing. And the implementation (so far) is: from abc import abstractmethod from collections import Sequence class Super(Sequence): # Gives us a list member for ABC methods to use. def __init__(self): self._list = [] # Abstract method in Sequence, implemented in terms of list. def __getitem__(self, index): return self._list.__getitem__(index) # Abstract method in Sequence, implemented in terms of list. def __len__(self): return self._list.__len__() # Not required. Makes printing behave like a list. def __repr__(self): return self._list.__repr__() Test it: In [34]: a = Super() In [35]: a Out[35]: [] In [36]: print a [] In [37]: len(a) Out[37]: 0 In [38]: a[0] --------------------------------------------------------------------------- IndexError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() /home/aaron/projects/test/test.py in __getitem__(self, index) 10 # Abstract method in Sequence, implemented in terms of list. 11 def __getitem__(self, index): ---> 12 return self._list.__getitem__(index) 13 14 # Abstract method in Sequence, implemented in terms of list. IndexError: list index out of range Just like a list. It's not abstract (for the moment) because we implemented both of Sequence's abstract methods. Now I want to add my bit of interface, which will be abstract in Super and therefore required to implement in any subclasses. And we'll cut to the chase and add subclasses that inherit from our ABC Super. from abc import abstractmethod from collections import Sequence class Super(Sequence): # Gives us a list member for ABC methods to use. def __init__(self): self._list = [] # Abstract method in Sequence, implemented in terms of list. def __getitem__(self, index): return self._list.__getitem__(index) # Abstract method in Sequence, implemented in terms of list. def __len__(self): return self._list.__len__() # Not required. Makes printing behave like a list. def __repr__(self): return self._list.__repr__() @abstractmethod def method1(): pass class Sub0(Super): pass class Sub1(Super): def __init__(self): self._list = [1, 2, 3] def method1(self): return [x**2 for x in self._list] def method2(self): return [x/2.0 for x in self._list] class Sub2(Super): def __init__(self): self._list = [10, 20, 30, 40] def method1(self): return [x+2 for x in self._list] We've added a new abstract method to Super, method1. This makes Super abstract again. A new class Sub0 which inherits from Super but does not implement method1, so it's also an ABC. Two new classes Sub1 and Sub2, which both inherit from Super. They both implement method1 from Super, so they're not abstract. Both implementations of method1 are different. Sub1 and Sub2 also both initialize themselves differently; in real life they might initialize themselves wildly differently. So you have two subclasses which both "is a" Super (they both implement Super's required interface) although their implementations are different. Also remember that Super, although an ABC, provides four non-abstract methods. So Super provides two things to subclasses: an implementation of collections.Sequence, and an additional abstract interface (the one abstract method) that subclasses must implement. Also, class Sub1 implements an additional method, method2, which is not part of Super's interface. Sub1 "is a" Super, but it also has additional capabilities. Test it: In [52]: a = Super() --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() TypeError: Can't instantiate abstract class Super with abstract methods method1 In [53]: a = Sub0() --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() TypeError: Can't instantiate abstract class Sub0 with abstract methods method1 In [54]: a = Sub1() In [55]: a Out[55]: [1, 2, 3] In [56]: b = Sub2() In [57]: b Out[57]: [10, 20, 30, 40] In [58]: print a, b [1, 2, 3] [10, 20, 30, 40] In [59]: a, b Out[59]: ([1, 2, 3], [10, 20, 30, 40]) In [60]: a.method1() Out[60]: [1, 4, 9] In [61]: b.method1() Out[61]: [12, 22, 32, 42] In [62]: a.method2() Out[62]: [0.5, 1.0, 1.5] [63]: a[:2] Out[63]: [1, 2] In [64]: a[0] = 5 --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /home/aaron/projects/test/<ipython console> in <module>() TypeError: 'Sub1' object does not support item assignment Super and Sub0 are abstract and can't be instantiated (lines 52 and 53). Sub1 and Sub2 are concrete and have an immutable Sequence interface (54 through 59). Sub1 and Sub2 are instantiated differently, and their method1 implementations are different (60, 61). Sub1 includes an additional method2, beyond what's required by Super (62). Any concrete Super acts like a list/Sequence (63). A collections.Sequence is immutable (64). Finally, a wart: In [65]: a._list Out[65]: [1, 2, 3] In [66]: a._list = [] In [67]: a Out[67]: [] Super._list is spelled with a single underscore. Double underscore would have protected it from this last bit, but would have broken the implementation of methods in subclasses. Not sure why; I think because double underscore is private, and private means private. So ultimately this whole scheme relies on a gentleman's agreement not to reach in and muck with Super._list directly, as in line 65 above. Would love to know if there's a safer way to do that.

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Error codes for C++

- by billy

#include <iostream> #include <iomanip> using namespace std; //Global constant variable declaration const int MaxRows = 8, MaxCols = 10, SEED = 10325; //Functions Declaration void PrintNameHeader(ostream& out); void Fill2DArray(double ary[][MaxCols]); void Print2DArray(const double ary[][MaxCols]); double GetTotal(const double ary[][MaxCols]); double GetAverage(const double ary[][MaxCols]); double GetRowTotal(const double ary[][MaxCols], int theRow); double GetColumnTotal(const double ary[][MaxCols], int theRow); double GetHighestInRow(const double ary[][MaxCols], int theRow); double GetLowestInRow(const double ary[][MaxCols], int theRow); double GetHighestInCol(const double ary[][MaxCols], int theCol); double GetLowestInCol(const double ary[][MaxCols], int theCol); double GetHighest(const double ary[][MaxCols], int& theRow, int& theCol); double GetLowest(const double ary[][MaxCols], int& theRow, int& theCol); int main() { int theRow; int theCol; PrintNameHeader(cout); cout << fixed << showpoint << setprecision(1); srand(static_cast<unsigned int>(SEED)); double ary[MaxRows][MaxCols]; cout << "The seed value for random number generator is: " << SEED << endl; cout << endl; Fill2DArray(ary); Print2DArray(ary); cout << " The Total for all the elements in this array is: " << setw(7) << GetTotal(ary) << endl; cout << "The Average of all the elements in this array is: " << setw(7) << GetAverage(ary) << endl; cout << endl; cout << "The sum of each row is:" << endl; for(int index = 0; index < MaxRows; index++) { cout << "Row " << (index + 1) << ": " << GetRowTotal(ary, theRow) << endl; } cout << "The highest and lowest of each row is: " << endl; for(int index = 0; index < MaxCols; index++) { cout << "Row " << (index + 1) << ": " << GetHighestInRow(ary, theRow) << " " << GetLowestInRow(ary, theRow) << endl; } cout << "The highest and lowest of each column is: " << endl; for(int index = 0; index < MaxCols; index++) { cout << "Col " << (index + 1) << ": " << GetHighestInCol(ary, theRow) << " " << GetLowestInCol(ary, theRow) << endl; } cout << "The highest value in all the elements in this array is: " << endl; cout << GetHighest(ary, theRow, theCol) << "[" << theRow << "]" << "[" << theCol << "]" << endl; cout << "The lowest value in all the elements in this array is: " << endl; cout << GetLowest(ary, theRow, theCol) << "[" << theRow << "]" << "[" << theCol << "]" << endl; return 0; } //Define Functions void PrintNameHeader(ostream& out) { out << "*******************************" << endl; out << "* *" << endl; out << "* C.S M10A Spring 2010 *" << endl; out << "* Programming Assignment 10 *" << endl; out << "* Due Date: Thurs. Mar. 25 *" << endl; out << "*******************************" << endl; out << endl; } void Fill2DArray(double ary[][MaxCols]) { for(int index1 = 0; index1 < MaxRows; index1++) { for(int index2= 0; index2 < MaxCols; index2++) { ary[index1][index2] = (rand()%1000)/10; } } } void Print2DArray(const double ary[][MaxCols]) { cout << " Column "; for(int index = 0; index < MaxCols; index++) { int column = index + 1; cout << " " << column << " "; } cout << endl; cout << " "; for(int index = 0; index < MaxCols; index++) { int column = index +1; cout << "----- "; } cout << endl; for(int index1 = 0; index1 < MaxRows; index1++) { cout << "Row " << (index1 + 1) << ":"; for(int index2= 0; index2 < MaxCols; index2++) { cout << setw(6) << ary[index1][index2]; } } } double GetTotal(const double ary[][MaxCols]) { double total = 0; for(int theRow = 0; theRow < MaxRows; theRow++) { total = total + GetRowTotal(ary, theRow); } return total; } double GetAverage(const double ary[][MaxCols]) { double total = 0, average = 0; total = GetTotal(ary); average = total / (MaxRows * MaxCols); return average; } double GetRowTotal(const double ary[][MaxCols], int theRow) { double sum = 0; for(int index = 0; index < MaxCols; index++) { sum = sum + ary[theRow][index]; } return sum; } double GetColumTotal(const double ary[][MaxCols], int theCol) { double sum = 0; for(int index = 0; index < theCol; index++) { sum = sum + ary[index][theCol]; } return sum; } double GetHighestInRow(const double ary[][MaxCols], int theRow) { double highest = 0; for(int index = 0; index < MaxCols; index++) { if(ary[theRow][index] > highest) highest = ary[theRow][index]; } return highest; } double GetLowestInRow(const double ary[][MaxCols], int theRow) { double lowest = 0; for(int index = 0; index < MaxCols; index++) { if(ary[theRow][index] < lowest) lowest = ary[theRow][index]; } return lowest; } double GetHighestInCol(const double ary[][MaxCols], int theCol) { double highest = 0; for(int index = 0; index < MaxRows; index++) { if(ary[index][theCol] > highest) highest = ary[index][theCol]; } return highest; } double GetLowestInCol(const double ary[][MaxCols], int theCol) { double lowest = 0; for(int index = 0; index < MaxRows; index++) { if(ary[index][theCol] < lowest) lowest = ary[index][theCol]; } return lowest; } double GetHighest(const double ary[][MaxCols], int& theRow, int& theCol) { theRow = 0; theCol = 0; double highest = ary[theRow][theCol]; for(int index = 0; index < MaxRows; index++) { for(int index1 = 0; index1 < MaxCols; index1++) { double highest = 0; if(ary[index1][theCol] > highest) { highest = ary[index][index1]; theRow = index; theCol = index1; } } } return highest; } double Getlowest(const double ary[][MaxCols], int& theRow, int& theCol) { theRow = 0; theCol = 0; double lowest = ary[theRow][theCol]; for(int index = 0; index < MaxRows; index++) { for(int index1 = 0; index1 < MaxCols; index1++) { double lowest = 0; if(ary[index1][theCol] < lowest) { lowest = ary[index][index1]; theRow = index; theCol = index1; } } } return lowest; } . 1>------ Build started: Project: teddy lab 10, Configuration: Debug Win32 ------ 1>Compiling... 1>lab 10.cpp 1>c:\users\owner\documents\visual studio 2008\projects\teddy lab 10\teddy lab 10\ lab 10.cpp(46) : warning C4700: uninitialized local variable 'theRow' used 1>c:\users\owner\documents\visual studio 2008\projects\teddy lab 10\teddy lab 10\ lab 10.cpp(62) : warning C4700: uninitialized local variable 'theCol' used 1>Linking... 1> lab 10.obj : error LNK2028: unresolved token (0A0002E0) "double __cdecl GetLowest(double const (* const)[10],int &,int &)" (?GetLowest@@$$FYANQAY09$$CBNAAH1@Z) referenced in function "int __cdecl main(void)" (?main@@$$HYAHXZ) 1> lab 10.obj : error LNK2019: unresolved external symbol "double __cdecl GetLowest(double const (* const)[10],int &,int &)" (?GetLowest@@$$FYANQAY09$$CBNAAH1@Z) referenced in function "int __cdecl main(void)" (?main@@$$HYAHXZ) 1>C:\Users\owner\Documents\Visual Studio 2008\Projects\ lab 10\Debug\ lab 10.exe : fatal error LNK1120: 2 unresolved externals 1>Build log was saved at "file://c:\Users\owner\Documents\Visual Studio 2008\Projects\ lab 10\teddy lab 10\Debug\BuildLog.htm" 1>teddy lab 10 - 3 error(s), 2 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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file doesn't open, running outside of debugger results in seg fault (c++)

- by misterich

Hello (and thanks in advance) I'm in a bit of a quandry, I cant seem to figure out why I'm seg faulting. A couple of notes: It's for a course -- and sadly I am required to use use C-strings instead of std::string. Please dont fix my code (I wont learn that way and I will keep bugging you). please just point out the flaws in my logic and suggest a different function/way. platform: gcc version 4.4.1 on Suse Linux 11.2 (2.6.31 kernel) Here's the code main.cpp: // /////////////////////////////////////////////////////////////////////////////////// // INCLUDES (C/C++ Std Library) #include <cstdlib> /// EXIT_SUCCESS, EXIT_FAILURE #include <iostream> /// cin, cout, ifstream #include <cassert> /// assert // /////////////////////////////////////////////////////////////////////////////////// // DEPENDENCIES (custom header files) #include "dict.h" /// Header for the dictionary class // /////////////////////////////////////////////////////////////////////////////////// // PRE-PROCESSOR CONSTANTS #define ENTER '\n' /// Used to accept new lines, quit program. #define SPACE ' ' /// One way to end the program // /////////////////////////////////////////////////////////////////////////////////// // CUSTOM DATA TYPES /// File Namespace -- keep it local namespace { /// Possible program prompts to display for the user. enum FNS_Prompts { fileName_, /// prints out the name of the file noFile_, /// no file was passed to the program tooMany_, /// more than one file was passed to the program noMemory_, /// Not enough memory to use the program usage_, /// how to use the program word_, /// ask the user to define a word. notFound_, /// the word is not in the dictionary done_, /// the program is closing normally }; } // /////////////////////////////////////////////////////////////////////////////////// // Namespace using namespace std; /// Nothing special in the way of namespaces // /////////////////////////////////////////////////////////////////////////////////// // FUNCTIONS /** prompt() prompts the user to do something, uses enum Prompts for parameter. */ void prompt(FNS_Prompts msg /** determines the prompt to use*/) { switch(msg) { case fileName_ : { cout << ENTER << ENTER << "The file name is: "; break; } case noFile_ : { cout << ENTER << ENTER << "...Sorry, a dictionary file is needed. Try again." << endl; break; } case tooMany_ : { cout << ENTER << ENTER << "...Sorry, you can only specify one dictionary file. Try again." << endl; break; } case noMemory_ : { cout << ENTER << ENTER << "...Sorry, there isn't enough memory available to run this program." << endl; break; } case usage_ : { cout << "USAGE:" << endl << " lookup.exe [dictionary file name]" << endl << endl; break; } case done_ : { cout << ENTER << ENTER << "like Master P says, \"Word.\"" << ENTER << endl; break; } case word_ : { cout << ENTER << ENTER << "Enter a word in the dictionary to get it's definition." << ENTER << "Enter \"?\" to get a sorted list of all words in the dictionary." << ENTER << "... Press the Enter key to quit the program: "; break; } case notFound_ : { cout << ENTER << ENTER << "...Sorry, that word is not in the dictionary." << endl; break; } default : { cout << ENTER << ENTER << "something passed an invalid enum to prompt(). " << endl; assert(false); /// something passed in an invalid enum } } } /** useDictionary() uses the dictionary created by createDictionary * - prompts user to lookup a word * - ends when the user enters an empty word */ void useDictionary(Dictionary &d) { char *userEntry = new char; /// user's input on the command line if( !userEntry ) // check the pointer to the heap { cout << ENTER << MEM_ERR_MSG << endl; exit(EXIT_FAILURE); } do { prompt(word_); // test code cout << endl << "----------------------------------------" << endl << "Enter something: "; cin.getline(userEntry, INPUT_LINE_MAX_LEN, ENTER); cout << ENTER << userEntry << endl; }while ( userEntry[0] != NIL && userEntry[0] != SPACE ); // GARBAGE COLLECTION delete[] userEntry; } /** Program Entry * Reads in the required, single file from the command prompt. * - If there is no file, state such and error out. * - If there is more than one file, state such and error out. * - If there is a single file: * - Create the database object * - Populate the database object * - Prompt the user for entry * main() will return EXIT_SUCCESS upon termination. */ int main(int argc, /// the number of files being passed into the program char *argv[] /// pointer to the filename being passed into tthe program ) { // EXECUTE /* Testing code * / char tempFile[INPUT_LINE_MAX_LEN] = {NIL}; cout << "enter filename: "; cin.getline(tempFile, INPUT_LINE_MAX_LEN, '\n'); */ // uncomment after successful debugging if(argc <= 1) { prompt(noFile_); prompt(usage_); return EXIT_FAILURE; /// no file was passed to the program } else if(argc > 2) { prompt(tooMany_); prompt(usage_); return EXIT_FAILURE; /// more than one file was passed to the program } else { prompt(fileName_); cout << argv[1]; // print out name of dictionary file if( !argv[1] ) { prompt(noFile_); prompt(usage_); return EXIT_FAILURE; /// file does not exist } /* file.open( argv[1] ); // open file numEntries >> in.getline(file); // determine number of dictionary objects to create file.close(); // close file Dictionary[ numEntries ](argv[1]); // create the dictionary object */ // TEMPORARY FILE FOR TESTING!!!! //Dictionary scrabble(tempFile); Dictionary scrabble(argv[1]); // creaate the dicitonary object //*/ useDictionary(scrabble); // prompt the user, use the dictionary } // exit return EXIT_SUCCESS; /// terminate program. } Dict.h/.cpp #ifndef DICT_H #define DICT_H // /////////////////////////////////////////////////////////////////////////////////// // DEPENDENCIES (Custom header files) #include "entry.h" /// class for dictionary entries // /////////////////////////////////////////////////////////////////////////////////// // PRE-PROCESSOR MACROS #define INPUT_LINE_MAX_LEN 256 /// Maximum length of each line in the dictionary file class Dictionary { public : // // Do NOT modify the public section of this class // typedef void (*WordDefFunc)(const char *word, const char *definition); Dictionary( const char *filename ); ~Dictionary(); const char *lookupDefinition( const char *word ); void forEach( WordDefFunc func ); private : // // You get to provide the private members // // VARIABLES int m_numEntries; /// stores the number of entries in the dictionary Entry *m_DictEntry_ptr; /// points to an array of class Entry // Private Functions }; #endif ----------------------------------- // /////////////////////////////////////////////////////////////////////////////////// // INCLUDES (C/C++ Std Library) #include <iostream> /// cout, getline #include <fstream> // ifstream #include <cstring> /// strchr // /////////////////////////////////////////////////////////////////////////////////// // DEPENDENCIES (custom header files) #include "dict.h" /// Header file required by assignment //#include "entry.h" /// Dicitonary Entry Class // /////////////////////////////////////////////////////////////////////////////////// // PRE-PROCESSOR MACROS #define COMMA ',' /// Delimiter for file #define ENTER '\n' /// Carriage return character #define FILE_ERR_MSG "The data file could not be opened. Program will now terminate." #pragma warning(disable : 4996) /// turn off MS compiler warning about strcpy() // /////////////////////////////////////////////////////////////////////////////////// // Namespace reference using namespace std; // /////////////////////////////////////////////////////////////////////////////////// // PRIVATE MEMBER FUNCTIONS /** * Sorts the dictionary entries. */ /* static void sortDictionary(?) { // sort through the words using qsort } */ /** NO LONGER NEEDED?? * parses out the length of the first cell in a delimited cell * / int getWordLength(char *str /// string of data to parse ) { return strcspn(str, COMMA); } */ // /////////////////////////////////////////////////////////////////////////////////// // PUBLIC MEMBER FUNCTIONS /** constructor for the class * - opens/reads in file * - creates initializes the array of member vars * - creates pointers to entry objects * - stores pointers to entry objects in member var * - ? sort now or later? */ Dictionary::Dictionary( const char *filename ) { // Create a filestream, open the file to be read in ifstream dataFile(filename, ios::in ); /* if( dataFile.fail() ) { cout << FILE_ERR_MSG << endl; exit(EXIT_FAILURE); } */ if( dataFile.is_open() ) { // read first line of data // TEST CODE in.getline(dataFile, INPUT_LINE_MAX_LEN) >> m_numEntries; // TEST CODE char temp[INPUT_LINE_MAX_LEN] = {NIL}; // TEST CODE dataFile.getline(temp,INPUT_LINE_MAX_LEN,'\n'); dataFile >> m_numEntries; /** Number of terms in the dictionary file * \todo find out how many lines in the file, subtract one, ingore first line */ //create the array of entries m_DictEntry_ptr = new Entry[m_numEntries]; // check for valid memory allocation if( !m_DictEntry_ptr ) { cout << MEM_ERR_MSG << endl; exit(EXIT_FAILURE); } // loop thru each line of the file, parsing words/def's and populating entry objects for(int EntryIdx = 0; EntryIdx < m_numEntries; ++EntryIdx) { // VARIABLES char *tempW_ptr; /// points to a temporary word char *tempD_ptr; /// points to a temporary def char *w_ptr; /// points to the word in the Entry object char *d_ptr; /// points to the definition in the Entry int tempWLen; /// length of the temp word string int tempDLen; /// length of the temp def string char tempLine[INPUT_LINE_MAX_LEN] = {NIL}; /// stores a single line from the file // EXECUTE // getline(dataFile, tempLine) // get a "word,def" line from the file dataFile.getline(tempLine, INPUT_LINE_MAX_LEN); // get a "word,def" line from the file // Parse the string tempW_ptr = tempLine; // point the temp word pointer at the first char in the line tempD_ptr = strchr(tempLine, COMMA); // point the def pointer at the comma *tempD_ptr = NIL; // replace the comma with a NIL ++tempD_ptr; // increment the temp def pointer // find the string lengths... +1 to account for terminator tempWLen = strlen(tempW_ptr) + 1; tempDLen = strlen(tempD_ptr) + 1; // Allocate heap memory for the term and defnition w_ptr = new char[ tempWLen ]; d_ptr = new char[ tempDLen ]; // check memory allocation if( !w_ptr && !d_ptr ) { cout << MEM_ERR_MSG << endl; exit(EXIT_FAILURE); } // copy the temp word, def into the newly allocated memory and terminate the strings strcpy(w_ptr,tempW_ptr); w_ptr[tempWLen] = NIL; strcpy(d_ptr,tempD_ptr); d_ptr[tempDLen] = NIL; // set the pointers for the entry objects m_DictEntry_ptr[ EntryIdx ].setWordPtr(w_ptr); m_DictEntry_ptr[ EntryIdx ].setDefPtr(d_ptr); } // close the file dataFile.close(); } else { cout << ENTER << FILE_ERR_MSG << endl; exit(EXIT_FAILURE); } } /** * cleans up dynamic memory */ Dictionary::~Dictionary() { delete[] m_DictEntry_ptr; /// thou shalt not have memory leaks. } /** * Looks up definition */ /* const char *lookupDefinition( const char *word ) { // print out the word ---- definition } */ /** * prints out the entire dictionary in sorted order */ /* void forEach( WordDefFunc func ) { // to sort before or now.... that is the question } */ Entry.h/cpp #ifndef ENTRY_H #define ENTRY_H // /////////////////////////////////////////////////////////////////////////////////// // INCLUDES (C++ Std lib) #include <cstdlib> /// EXIT_SUCCESS, NULL // /////////////////////////////////////////////////////////////////////////////////// // PRE-PROCESSOR MACROS #define NIL '\0' /// C-String terminator #define MEM_ERR_MSG "Memory allocation has failed. Program will now terminate." // /////////////////////////////////////////////////////////////////////////////////// // CLASS DEFINITION class Entry { public: Entry(void) : m_word_ptr(NULL), m_def_ptr(NULL) { /* default constructor */ }; void setWordPtr(char *w_ptr); /// sets the pointer to the word - only if the pointer is empty void setDefPtr(char *d_ptr); /// sets the ponter to the definition - only if the pointer is empty /// returns what is pointed to by the word pointer char getWord(void) const { return *m_word_ptr; } /// returns what is pointed to by the definition pointer char getDef(void) const { return *m_def_ptr; } private: char *m_word_ptr; /** points to a dictionary word */ char *m_def_ptr; /** points to a dictionary definition */ }; #endif -------------------------------------------------- // /////////////////////////////////////////////////////////////////////////////////// // DEPENDENCIES (custom header files) #include "entry.h" /// class header file // /////////////////////////////////////////////////////////////////////////////////// // PUBLIC FUNCTIONS /* * only change the word member var if it is in its initial state */ void Entry::setWordPtr(char *w_ptr) { if(m_word_ptr == NULL) { m_word_ptr = w_ptr; } } /* * only change the def member var if it is in its initial state */ void Entry::setDefPtr(char *d_ptr) { if(m_def_ptr == NULL) { m_word_ptr = d_ptr; } }

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Trying to convert simple midlet application to Android application but running into problems.

- by chobo2

Hi I am trying to do some threading in Android so I took an old threading assignment I had done fora midlet and took out the midlet code and replaced it with android code(such as textview). package com.assignment1; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class Threading extends Activity { private TextView tortose; private TextView hare; private Thread hareThread; private Thread torotoseThread; private int num = 0; private int num2 = 0; public Threading() { } /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tortose = (TextView) findViewById(R.id.TextView01); hare = (TextView) findViewById(R.id.TextView02); Hare newHare = new Hare(); hareThread = new Thread(newHare); hareThread.start(); Torotose newTortose = new Torotose(); torotoseThread = new Thread(newTortose); torotoseThread.start(); //updateDisplay(); } private synchronized void check(int value1, int value2) { if((value1-value2) >= 10) { try { wait(); } catch(Exception ex) { System.out.println(ex); } } } private synchronized void getGoing(int value1, int value2) { if((value1-value2) == 0) { try { notify(); } catch(Exception ex) { System.out.println(ex); } } } private class Hare extends Thread { public void run() { while(true) { num++; hare.setText(Integer.toString(num)); check(num, num2); try { // are threads different in andriod apps? Thread.sleep(100); // hareThread.sleep(100); } catch(Exception ex) { System.out.println(ex); } } } } private class Torotose extends Thread { public void run() { while(true) { num2++; tortose.setText(Integer.toString(num2)); getGoing(num,num2); try { Thread.sleep(200); //torotoseThread.sleep(200); } catch(Exception ex) { System.out.println(ex); } } } } } First it wanted me to change my threads to like static threads.So is this just how Android does it? Next when I run this code it just crashes with some unexpected error. I am not sure what the error is but when I try to debug it and goes to like to create a new "hare" object it shows me this. // Compiled from ClassLoader.java (version 1.5 : 49.0, super bit) public abstract class java.lang.ClassLoader { // Method descriptor #8 ()V // Stack: 3, Locals: 1 protected ClassLoader(); 0 aload_0 [this] 1 invokespecial java.lang.Object() [1] 4 new java.lang.RuntimeException [2] 7 dup 8 ldc <String "Stub!"> [3] 10 invokespecial java.lang.RuntimeException(java.lang.String) [4] 13 athrow Line numbers: [pc: 0, line: 4] Local variable table: [pc: 0, pc: 14] local: this index: 0 type: java.lang.ClassLoader // Method descriptor #14 (Ljava/lang/ClassLoader;)V // Stack: 3, Locals: 2 protected ClassLoader(java.lang.ClassLoader parentLoader); 0 aload_0 [this] 1 invokespecial java.lang.Object() [1] 4 new java.lang.RuntimeException [2] 7 dup 8 ldc <String "Stub!"> [3] 10 invokespecial java.lang.RuntimeException(java.lang.String) [4] 13 athrow Line numbers: [pc: 0, line: 5] Local variable table: [pc: 0, pc: 14] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 14] local: parentLoader index: 1 type: java.lang.ClassLoader // Method descriptor #17 ()Ljava/lang/ClassLoader; // Stack: 3, Locals: 0 public static java.lang.ClassLoader getSystemClassLoader(); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 6] // Method descriptor #19 (Ljava/lang/String;)Ljava/net/URL; // Stack: 3, Locals: 1 public static java.net.URL getSystemResource(java.lang.String resName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 7] Local variable table: [pc: 0, pc: 10] local: resName index: 0 type: java.lang.String // Method descriptor #23 (Ljava/lang/String;)Ljava/util/Enumeration; // Signature: (Ljava/lang/String;)Ljava/util/Enumeration<Ljava/net/URL;>; // Stack: 3, Locals: 1 public static java.util.Enumeration getSystemResources(java.lang.String resName) throws java.io.IOException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 8] Local variable table: [pc: 0, pc: 10] local: resName index: 0 type: java.lang.String // Method descriptor #29 (Ljava/lang/String;)Ljava/io/InputStream; // Stack: 3, Locals: 1 public static java.io.InputStream getSystemResourceAsStream(java.lang.String resName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 9] Local variable table: [pc: 0, pc: 10] local: resName index: 0 type: java.lang.String // Method descriptor #31 ([BII)Ljava/lang/Class; // Signature: ([BII)Ljava/lang/Class<*>; // Stack: 3, Locals: 4 protected final java.lang.Class defineClass(byte[] classRep, int offset, int length) throws java.lang.ClassFormatError; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 10] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: classRep index: 1 type: byte[] [pc: 0, pc: 10] local: offset index: 2 type: int [pc: 0, pc: 10] local: length index: 3 type: int // Method descriptor #39 (Ljava/lang/String;[BII)Ljava/lang/Class; // Signature: (Ljava/lang/String;[BII)Ljava/lang/Class<*>; // Stack: 3, Locals: 5 protected final java.lang.Class defineClass(java.lang.String className, byte[] classRep, int offset, int length) throws java.lang.ClassFormatError; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 11] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String [pc: 0, pc: 10] local: classRep index: 2 type: byte[] [pc: 0, pc: 10] local: offset index: 3 type: int [pc: 0, pc: 10] local: length index: 4 type: int // Method descriptor #42 (Ljava/lang/String;[BIILjava/security/ProtectionDomain;)Ljava/lang/Class; // Signature: (Ljava/lang/String;[BIILjava/security/ProtectionDomain;)Ljava/lang/Class<*>; // Stack: 3, Locals: 6 protected final java.lang.Class defineClass(java.lang.String className, byte[] classRep, int offset, int length, java.security.ProtectionDomain protectionDomain) throws java.lang.ClassFormatError; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 12] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String [pc: 0, pc: 10] local: classRep index: 2 type: byte[] [pc: 0, pc: 10] local: offset index: 3 type: int [pc: 0, pc: 10] local: length index: 4 type: int [pc: 0, pc: 10] local: protectionDomain index: 5 type: java.security.ProtectionDomain // Method descriptor #46 (Ljava/lang/String;Ljava/nio/ByteBuffer;Ljava/security/ProtectionDomain;)Ljava/lang/Class; // Signature: (Ljava/lang/String;Ljava/nio/ByteBuffer;Ljava/security/ProtectionDomain;)Ljava/lang/Class<*>; // Stack: 3, Locals: 4 protected final java.lang.Class defineClass(java.lang.String name, java.nio.ByteBuffer b, java.security.ProtectionDomain protectionDomain) throws java.lang.ClassFormatError; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 13] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: name index: 1 type: java.lang.String [pc: 0, pc: 10] local: b index: 2 type: java.nio.ByteBuffer [pc: 0, pc: 10] local: protectionDomain index: 3 type: java.security.ProtectionDomain // Method descriptor #52 (Ljava/lang/String;)Ljava/lang/Class; // Signature: (Ljava/lang/String;)Ljava/lang/Class<*>; // Stack: 3, Locals: 2 protected java.lang.Class findClass(java.lang.String className) throws java.lang.ClassNotFoundException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 14] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String // Method descriptor #52 (Ljava/lang/String;)Ljava/lang/Class; // Signature: (Ljava/lang/String;)Ljava/lang/Class<*>; // Stack: 3, Locals: 2 protected final java.lang.Class findLoadedClass(java.lang.String className); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 15] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String // Method descriptor #52 (Ljava/lang/String;)Ljava/lang/Class; // Signature: (Ljava/lang/String;)Ljava/lang/Class<*>; // Stack: 3, Locals: 2 protected final java.lang.Class findSystemClass(java.lang.String className) throws java.lang.ClassNotFoundException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 16] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String // Method descriptor #17 ()Ljava/lang/ClassLoader; // Stack: 3, Locals: 1 public final java.lang.ClassLoader getParent(); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 17] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader // Method descriptor #19 (Ljava/lang/String;)Ljava/net/URL; // Stack: 3, Locals: 2 public java.net.URL getResource(java.lang.String resName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 18] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: resName index: 1 type: java.lang.String // Method descriptor #23 (Ljava/lang/String;)Ljava/util/Enumeration; // Signature: (Ljava/lang/String;)Ljava/util/Enumeration<Ljava/net/URL;>; // Stack: 3, Locals: 2 public java.util.Enumeration getResources(java.lang.String resName) throws java.io.IOException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 19] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: resName index: 1 type: java.lang.String // Method descriptor #29 (Ljava/lang/String;)Ljava/io/InputStream; // Stack: 3, Locals: 2 public java.io.InputStream getResourceAsStream(java.lang.String resName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 20] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: resName index: 1 type: java.lang.String // Method descriptor #52 (Ljava/lang/String;)Ljava/lang/Class; // Signature: (Ljava/lang/String;)Ljava/lang/Class<*>; // Stack: 3, Locals: 2 public java.lang.Class loadClass(java.lang.String className) throws java.lang.ClassNotFoundException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 21] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String // Method descriptor #62 (Ljava/lang/String;Z)Ljava/lang/Class; // Signature: (Ljava/lang/String;Z)Ljava/lang/Class<*>; // Stack: 3, Locals: 3 protected java.lang.Class loadClass(java.lang.String className, boolean resolve) throws java.lang.ClassNotFoundException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 22] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: className index: 1 type: java.lang.String [pc: 0, pc: 10] local: resolve index: 2 type: boolean // Method descriptor #67 (Ljava/lang/Class;)V // Signature: (Ljava/lang/Class<*>;)V // Stack: 3, Locals: 2 protected final void resolveClass(java.lang.Class clazz); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 23] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: clazz index: 1 type: java.lang.Class Local variable type table: [pc: 0, pc: 10] local: clazz index: 1 type: java.lang.Class<?> // Method descriptor #19 (Ljava/lang/String;)Ljava/net/URL; // Stack: 3, Locals: 2 protected java.net.URL findResource(java.lang.String resName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 24] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: resName index: 1 type: java.lang.String // Method descriptor #23 (Ljava/lang/String;)Ljava/util/Enumeration; // Signature: (Ljava/lang/String;)Ljava/util/Enumeration<Ljava/net/URL;>; // Stack: 3, Locals: 2 protected java.util.Enumeration findResources(java.lang.String resName) throws java.io.IOException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 25] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: resName index: 1 type: java.lang.String // Method descriptor #76 (Ljava/lang/String;)Ljava/lang/String; // Stack: 3, Locals: 2 protected java.lang.String findLibrary(java.lang.String libName); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 26] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: libName index: 1 type: java.lang.String // Method descriptor #79 (Ljava/lang/String;)Ljava/lang/Package; // Stack: 3, Locals: 2 protected java.lang.Package getPackage(java.lang.String name); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 27] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: name index: 1 type: java.lang.String // Method descriptor #81 ()[Ljava/lang/Package; // Stack: 3, Locals: 1 protected java.lang.Package[] getPackages(); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 28] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader // Method descriptor #83 (Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/net/URL;)Ljava/lang/Package; // Stack: 3, Locals: 9 protected java.lang.Package definePackage(java.lang.String name, java.lang.String specTitle, java.lang.String specVersion, java.lang.String specVendor, java.lang.String implTitle, java.lang.String implVersion, java.lang.String implVendor, java.net.URL sealBase) throws java.lang.IllegalArgumentException; 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 29] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: name index: 1 type: java.lang.String [pc: 0, pc: 10] local: specTitle index: 2 type: java.lang.String [pc: 0, pc: 10] local: specVersion index: 3 type: java.lang.String [pc: 0, pc: 10] local: specVendor index: 4 type: java.lang.String [pc: 0, pc: 10] local: implTitle index: 5 type: java.lang.String [pc: 0, pc: 10] local: implVersion index: 6 type: java.lang.String [pc: 0, pc: 10] local: implVendor index: 7 type: java.lang.String [pc: 0, pc: 10] local: sealBase index: 8 type: java.net.URL // Method descriptor #94 (Ljava/lang/Class;[Ljava/lang/Object;)V // Signature: (Ljava/lang/Class<*>;[Ljava/lang/Object;)V // Stack: 3, Locals: 3 protected final void setSigners(java.lang.Class c, java.lang.Object[] signers); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 30] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: c index: 1 type: java.lang.Class [pc: 0, pc: 10] local: signers index: 2 type: java.lang.Object[] Local variable type table: [pc: 0, pc: 10] local: c index: 1 type: java.lang.Class<?> // Method descriptor #100 (Ljava/lang/String;Z)V // Stack: 3, Locals: 3 public void setClassAssertionStatus(java.lang.String cname, boolean enable); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 31] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: cname index: 1 type: java.lang.String [pc: 0, pc: 10] local: enable index: 2 type: boolean // Method descriptor #100 (Ljava/lang/String;Z)V // Stack: 3, Locals: 3 public void setPackageAssertionStatus(java.lang.String pname, boolean enable); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 32] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: pname index: 1 type: java.lang.String [pc: 0, pc: 10] local: enable index: 2 type: boolean // Method descriptor #106 (Z)V // Stack: 3, Locals: 2 public void setDefaultAssertionStatus(boolean enable); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 33] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader [pc: 0, pc: 10] local: enable index: 1 type: boolean // Method descriptor #8 ()V // Stack: 3, Locals: 1 public void clearAssertionStatus(); 0 new java.lang.RuntimeException [2] 3 dup 4 ldc <String "Stub!"> [3] 6 invokespecial java.lang.RuntimeException(java.lang.String) [4] 9 athrow Line numbers: [pc: 0, line: 34] Local variable table: [pc: 0, pc: 10] local: this index: 0 type: java.lang.ClassLoader } So I am not sure where I went wrong. Thanks

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Having an issue with overwriting an element of a file correctly (numeric)

- by IngeniousHax

This is an ATM style program, but currently it doesn't do exactly what I need it to do... I need to get the current balance, and when money is transferred from either checking or savings, it should add it to checking and subtract it from savings. which is does, but not correctly... Input example -=[ Funds Transfer ]=- -=[ Savings to Checking ]=- Account Name: nomadic Amount to transfer: $400 New Balance in Checking: $900 // original was 500 New Balance in Savings: $7.7068e+012 // this should now be 1100... Here is my code, it's a lot of code, but there are no errors, so throwing it into an IDE and compiling should be fairly quick for whoever would like to help. mainBankClass.h mainBankClass.h #ifndef MAINBANKCLASS_H #define MAINBANKCLASS_H #include <iostream> #include <fstream> #include <string> using namespace std; class Banking { protected: string checkAcctName, saveAcctName; // Name on the account int acctNumber[13]; // Account number float acctBalance, initSaveDeposit, initCheckDeposit, depAmt; // amount in account, and amount to deposit public: char getBalanceChoice(); // Get name on account for displaying relevant information char newAccountMenu(); // Create a new account and assign it a random account number void invalid(char *); // If an invalid option is chosen char menu(); // Print the main menu for the user. virtual float deposit(){ return 0; } // virtual function for deposits // virtual float withdrawal() = 0; // Virtual function for withdrawals void fatal(char *); // Handles fatal errors. Banking(); }; class Checking : public Banking { public: friend ostream operator<<(ostream &, Checking &); friend istream operator>>(istream &, Checking &); Checking operator <= (const Checking &) const; void newCheckingAccount(); void viewCheckingBalance(); void transferFromSaving(); float deposit() { return (acctBalance += depAmt); } }; class Saving : public Banking { public: friend ostream &operator<<(ostream &, Saving &); friend istream &operator>>(istream &, Saving &); Saving operator <= (const Saving &) const; void newSavingAccount(); void viewSavingBalance(); void transferFromChecking(); float deposit() { return (acctBalance += depAmt); } }; class checkAndSave : public Banking { public: void newCheckAndSave(); void viewBothBalances(); }; #endif bankAccount.cpp #include <iostream> #include <sstream> #include <string> #include <iomanip> #include <fstream> #include <time.h> #include "MainBankClass.h" /*****************************\ | BANKING CONSTRUCTOR | \*****************************/ Banking::Banking() { string acctName; // Name on the account acctNumber[13] = 0; // Account number acctBalance = 0; initCheckDeposit = 0; initSaveDeposit = 0; depAmt = 0; }; /********************************\ | The following code is to print the menu | | and recieve the users choice on what | | they want to do with the ATM | \********************************/ char Banking::menu() { char choice; system("cls"); cout << "\t\t -=[ Main Menu ]=- \n\n" << "\tA) Create New Account\n" << "\tB) View Account Balance\n" << "\tC) Transfer Funds From Checking To Savings\n" << "\tD) Transfer Funds From Savings To Checking\n" << "\tE) Exit\n" << "\n\n\tSelection: "; cin >> choice; cin.ignore(); choice = toupper(choice); while(!isalpha(choice)) { invalid("[!!] Invalid selection.\n[!!] Choose a valid option: "); cin >> choice; cin.ignore(); } return choice; } /*********************\ | Will read in account choic | | and display it for the user | \*********************/ char Banking::getBalanceChoice() { char choice; fstream saveFile("saving.dat", ios::in | ios::beg); system("cls"); cout << "\t\t -=[ View Account Balance ]=-\n\n"; cout << "A) View Checking Account\n" << "B) View Saving Account\n" << "C) View Checking \\ Saving Account\n" << endl; cout << "Choice: "; cin >> choice; choice = toupper(choice); if(!isalpha(choice)) fatal(" [!!] Invalid Choice"); return choice; } /***************************\ | Incase an invalid decision to made | | this throws the error message sent | | to it by the calling area | \***************************/ void Banking::invalid(char *msg) { cout << msg; } /*************************\ | Used if files can not be opened | | and exits with code 251: | | miscommunication with server | \*************************/ void Banking::fatal(char *msg) { cout << msg; exit(1); } /***************************\ | Create an account, either checking | | or savings, or both. | | Must should create a randomly | | generated account number that will | | correspond with each account. | \***************************/ /************************\ NOTE:: WILL BE UPDATED TO CONTAIN A PIN FOR ACCOUNT VERIFICATION *************************/ char Banking::newAccountMenu() { srand(time(NULL)); // Seed random generator with time initialized to NULL char acctChoice; // choice for the account type ofstream checkFile("checking.dat", ios::out | ios::app); // For saving checking accounts ofstream saveFile("saving.dat", ios::out | ios::app); // For saving savings accounts system("cls"); cout << "\t\t-=[ New Account Creation ]=-\n\n" << endl; cout << "A) Checking Account\n" << "B) Savings Account\n" << "C) Checking and Saving Account\n" << endl; cout << "New account type: "; cin >> acctChoice; acctChoice = toupper(acctChoice); cin.clear(); cin.sync(); return acctChoice; } /********************************************************************* ********************************************************************** CHECKING ACCOUNT CODE ********************************************************************** **********************************************************************/ // New Checking Account Creation void Checking::newCheckingAccount() { system("cls"); ofstream checkFile("checking.dat", ios::out | ios::app); // For saving checking accounts cout << "\t\t -=[ New Checking Account ]=- \n" << endl; cout << "Name of the main holder to be on the account: "; getline(cin, checkAcctName); cout << "Initial deposit amount: $"; cin >> initCheckDeposit; if(initCheckDeposit <= 0) { while(initCheckDeposit <= 0) { invalid("[!!] 0 or negative amount entered\nMaybe a typo?\n"); cout << "Deposit Amount: $"; cin >> initCheckDeposit; } } if(!checkFile) fatal("[!!] Fatal Error 251: Miscommunication with server\n"); checkFile << checkAcctName << endl; for(int j = 0; j < 13; j++) { acctNumber[j] = (rand() % 10); // Build a random checking account number checkFile << acctNumber[j]; } checkFile << endl; checkFile << initCheckDeposit << endl; checkFile.close(); } void Checking::viewCheckingBalance() { fstream checkFile("checking.dat", ios::in | ios::beg); string name; int i = 0; double balance = 0; system("cls"); cout << "\t\t -=[ View Checking Account ]=-\n\n" << endl; cout << "Account Name: "; cin.sync(); getline(cin, name); getline(checkFile, checkAcctName); while(name != checkAcctName && !checkFile.fail()) { i++; getline(checkFile, checkAcctName); } if(name == checkAcctName) { system("cls"); cout << "\t\t -=[ Checking Account Balance ]=-\n\n" << endl; cout << "Account Name: " << checkAcctName << "\n"; cout << "Account Number: "; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; checkFile.get(input_number); converter << input_number; converter >> acctNumber[j]; cout << acctNumber[j]; } // if balance a problem, try the below commented out line // checkFile.ignore(numeric_limits<streamsize>::max(), '\n'); cout << endl; checkFile >> acctBalance; cout << "Balance: $" << fixed << showpoint << setprecision(2) << acctBalance << endl; } else fatal("[!!] Invalid Account\n"); checkFile.close(); getchar(); } void Checking::transferFromSaving() // Move funds FROM SAVINGS to CHECKING { system("cls"); string name; long checkPos = 0; long savePos = 0; float savingBalance = 0; string saveAcctName; int i = 0; cin.clear(); fstream saveFile("saving.dat", ios::in | ios::out | ios::beg); fstream checkFile("checking.dat", ios::in | ios::out | ios::beg); cout << "\t\t-=[ Funds Transfer ]=-" << endl; cout << "\t\t-=[ Savings to Checking ]=-" << endl; cout << "Account Name: "; cin.sync(); getline(cin, name); getline(checkFile, checkAcctName); while(name != checkAcctName && !checkFile.fail()) { i++; getline(checkFile, checkAcctName); } getline(saveFile, saveAcctName); while(name != saveAcctName && !saveFile.fail()) { i = 0; i++; getline(saveFile, saveAcctName); } if(name == checkAcctName) { cout << "Amount to transfer: $"; float depAmt = 0; cin >> depAmt; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; checkFile.get(input_number); converter << input_number; converter >> acctNumber[j]; } checkPos = checkFile.tellg(); // if the file is found, get the position of acctBalance and store it in ptrPos checkFile.seekg(checkPos); checkFile >> acctBalance; savePos = saveFile.tellg(); saveFile.seekg(savePos); // sending the cursor in the file to ptrPos + 1 to ignore white space saveFile >> savingBalance; if(savingBalance < depAmt) // if checking account does not have enough funds, exit with NSF code fatal("[!!] Insufficient Funds\n"); acctBalance += depAmt; // can be changed to an overloaded operator savingBalance -= depAmt; // can be changed to an overloaded operator checkFile.seekp(checkPos); // go to position previously set above checkFile << acctBalance; // write new balance to checkFile saveFile.seekp(savePos); // same thing as above comment saveFile << savingBalance; // write new balance to saveFile cout << "New Balance in Checking: $" << acctBalance << endl; // will be removed later cout << "New Balance in Savings: $" << savingBalance << endl; // will be removed later aswell } else fatal("[!!] Linked accounts do not exist.\n"); // if account is not found saveFile.close(); checkFile.close(); } /******************************************************** ******************************************************** SAVING ACCOUNT CODE ********************************************************* *********************************************************/ void Saving::newSavingAccount() { system("cls"); ofstream saveFile("saving.dat", ios::out | ios::app); // For saving savings accounts cout << "\t\t -=[ New Savings Account ]=- \n" << endl; cout << "Name of the main holder to be on account: "; getline(cin, saveAcctName); cout << "Deposit Amount: $"; cin >> initSaveDeposit; if(initSaveDeposit <= 0) { while(initSaveDeposit <= 0) { invalid("[!!]0 or negative value entered.\nPerhaps a typo?\n"); cout << "Deposit amount: $"; cin >> initSaveDeposit; } } if(!saveFile) fatal("[!!] Fatal Error 251: Miscommunication with server\n"); saveFile << saveAcctName << endl; for(int j = 0; j < 13; j++) { acctNumber[j] = (rand() % 10); saveFile << acctNumber[j]; } saveFile << endl; saveFile << initSaveDeposit << endl; saveFile.close(); } void Saving::viewSavingBalance() { string name; int i = 0; fstream saveFile("saving.dat", ios::in | ios::beg); cin.clear(); system("cls"); cout << "\t\t -=[ View Saving Account ]=-\n\n" << endl; cout << "Account Name: "; cin.sync(); getline(cin, name); getline(saveFile, saveAcctName); while(name != saveAcctName && !saveFile.fail()) { i++; getline(saveFile, saveAcctName); } if(name == saveAcctName) { system("cls"); cout << "\t\t -=[ Saving Account Balance ]=-\n\n" << endl; cout << "Account Name: " << saveAcctName << "\n"; cout << "Account Number: "; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; saveFile.get(input_number); converter << input_number; converter >> acctNumber[j]; cout << acctNumber[j]; } // if balance a problem, try the below commented out line // checkFile.ignore(numeric_limits<streamsize>::max(), '\n'); cout << endl; saveFile >> acctBalance; cout << "Balance: $" << fixed << showpoint << setprecision(2) << acctBalance << endl; } else fatal("[!!] Invalid Account\n"); saveFile.close(); getchar(); } // NEED TO WORK ON THIS PORTION TOMORROW AND MONDAY, ADD OVERLOADED OPS FOR ASSIGNMENT!!!!!!! void Saving::transferFromChecking() // This is to take money FROM checking and ADD IT TO SAVING { system("cls"); string name; long savePos = 0; long checkPos = 0; float checkingBalance = 0; string checkAcctName; int i = 0; cin.clear(); fstream saveFile("saving.dat", ios::in | ios::out | ios::beg); fstream checkFile("checking.dat", ios::in | ios::out | ios::beg); cout << "\t\t-=[ Funds Transfer ]=-" << endl; cout << "\t\t-=[ Checking to Savings ]=-" << endl; cout << "Account Name: "; cin.sync(); getline(cin, name); getline(saveFile, saveAcctName); getline(checkFile, checkAcctName); while(name != saveAcctName && name != checkAcctName && !saveFile.fail() && !checkFile.fail()) { i++; getline(saveFile, saveAcctName); getline(checkFile, checkAcctName); } if(name == saveAcctName) { cout << "Amount to transfer: $"; float depAmt = 0; cin >> depAmt; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; saveFile.get(input_number); converter << input_number; converter >> acctNumber[j]; } savePos = saveFile.tellg(); // if the file is found, get the position of acctBalance and store it in ptrPos saveFile.seekg(savePos); saveFile >> acctBalance; checkPos = checkFile.tellg(); checkFile.seekg(checkPos); // if file is found, store current position of the cursor to ptrPos checkFile >> checkingBalance; if(checkingBalance < depAmt) // if checking account does not have enough funds, exit with NSF code fatal("[!!] Insufficient Funds\n"); // Can also place overloaded op here acctBalance += depAmt; // can be changed to an overloaded operator checkingBalance -= depAmt; // can be changed to an overloaded operator saveFile.seekg(savePos); // go to position previously set above saveFile << acctBalance; // write new balance to saveFile checkFile.seekg(checkPos); // same thing as above comment checkFile << checkingBalance; // write new balance to checkFile cout << "New Balance in Savings: $" << acctBalance << endl; // will be removed later cout << "New Balance in Checking: $" << checkingBalance << endl; // will be removed later aswell } else fatal("[!!] Linked accounts do not exist.\n"); // if account is not found saveFile.close(); checkFile.close(); } /******************************************** ******************************************** CHECK AND SAVE CODE ********************************************** **********************************************/ void checkAndSave::newCheckAndSave() { system("cls"); ofstream saveFile("saving.dat", ios::out | ios::app); // For saving savings accounts ofstream checkFile("checking.dat", ios::out | ios::app); // For saving checking accounts cout << "\t -=[ New Checking & Saving Account ]=- \n" << endl; cout << "Name of the main holder to be on account: "; getline(cin, checkAcctName); saveAcctName = checkAcctName; cout << "Checking Deposit Amount: $"; cin >> initCheckDeposit; if(initCheckDeposit <= 0) { while(initCheckDeposit <= 0) { invalid("[!!] 0 or negative amount entered\nMaybe a typo?\n"); cout << "Deposit Amount: $"; cin >> initCheckDeposit; } } cout << "Saving Deposit Amount: $"; cin >> initSaveDeposit; if(initSaveDeposit <= 0) { while(initSaveDeposit <= 0) { invalid("[!!]0 or negative value entered.\nPerhaps a typo?\n"); cout << "Deposit amount: $"; cin >> initSaveDeposit; } } if(!saveFile || !checkFile) fatal("[!!] Fatal Error 251: Miscommunication with server\n"); checkFile << checkAcctName << endl; saveFile << saveAcctName << endl; for(int j = 0; j < 13; j++) { acctNumber[j] = (rand() % 10); checkFile << acctNumber[j]; saveFile << acctNumber[j]; } saveFile << endl; saveFile << initSaveDeposit << endl; checkFile << endl; checkFile << initCheckDeposit << endl; checkFile.close(); saveFile.close(); } void checkAndSave::viewBothBalances() { string name; int i = 0; fstream checkFile("checking.dat", ios::in | ios::beg); fstream saveFile("saving.dat", ios::in | ios::beg); system("cls"); cin.clear(); cout << "\t-=[ Saving & Checking Account Balance ]=-\n\n" << endl; cout << "Account Name: "; cin.sync(); getline(cin, name); getline(checkFile, checkAcctName); saveAcctName = name; /**********************\ | Checking Account portion | | of the checking & savings | | overview | \**********************/ while(name != checkAcctName && !checkFile.fail()) { i++; getline(checkFile, checkAcctName); } system("cls"); if(name != checkAcctName && checkFile.fail()) invalid("\n\n[!!] No Checking Account Found\n"); cout << "\t\t -=[ Checking Account ]=- \n" << endl; cout << "Account Name: " << checkAcctName << "\n"; cout << "Account Number: "; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; checkFile.get(input_number); converter << input_number; converter >> acctNumber[j]; cout << acctNumber[j]; } // if balance a problem, try the below commented out line // checkFile.ignore(numeric_limits<streamsize>::max(), '\n'); cout << endl; checkFile >> acctBalance; cout << "Balance: $" << fixed << showpoint << setprecision(2) << acctBalance << endl; /*********************\ | Saving Account portion | | of the checking & saving | | overview | \*********************/ getline(saveFile, saveAcctName); while(name != saveAcctName && !saveFile.fail()) { i++; getline(saveFile, saveAcctName); } if(name != saveAcctName && saveFile.fail()) invalid("\n\n[!!] No Saving Account Found\n"); if(name == saveAcctName) { cout << "\t\t -=[ Saving Account ]=-\n\n" << endl; cout << "Account Name: " << saveAcctName << "\n"; cout << "Account Number: "; for(int j = 0; j < 13; j++) { char input_number; stringstream converter; saveFile.get(input_number); converter << input_number; converter >> acctNumber[j]; cout << acctNumber[j]; } // if balance a problem, try the below commented out line // checkFile.ignore(numeric_limits<streamsize>::max(), '\n'); cout << endl; saveFile >> acctBalance; cout << "Balance: $" << fixed << showpoint << setprecision(2) << acctBalance << endl; } if(name != saveAcctName && name != checkAcctName && saveFile.fail() && checkFile.fail()) fatal("[!!] No Accounts Have Been Found\n"); checkFile.close(); saveFile.close(); getchar(); } Main.cpp #include <iostream> #include "MainBankClass.h" using namespace std; int main() { Banking bank; Checking check; Saving save; checkAndSave CanS; char choice; choice = bank.menu(); // Call the banking menu switch(choice) { case 'A': choice = bank.newAccountMenu(); switch(choice) { case 'A': check.newCheckingAccount(); break; case 'B': save.newSavingAccount(); break; case 'C': CanS.newCheckAndSave(); break; default: system("cls"); bank.fatal("[!!] Invalid option\n"); break; } break; /***********************************************/ case 'B': choice = bank.getBalanceChoice(); switch(choice) { case 'A': check.viewCheckingBalance(); break; case 'B': save.viewSavingBalance(); break; case 'C': CanS.viewBothBalances(); break; default: bank.fatal("Invalid decision\n"); break; } /*************************************************/ break; case 'C': check.transferFromSaving(); break; case 'D': save.transferFromChecking(); break; case 'E': system("cls"); cout << "\t\t-=[ Disconnecting From System ]=-\n"; cout << "\t\t\t Thank you" << endl; cout << "\t\t Have a nice day!" << endl; exit(1); break; default: system("cls"); bank.invalid("\n\n\n\n\t\t [+] Invalid Selection \n\t\t[+] Disconnecting From System \n\t\t\tGood-bye \n\n\n\n\n\n\n"); exit(1); break; } return 0; }

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