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  • Inheritance and choose constructor from base class

    - by myle
    My question is rather simple, but I am stuck. How can I choose the desired constructor from base class? // node.h #ifndef NODE_H #define NODE_H #include <vector> // definition of an exception-class class WrongBoundsException { }; class Node { public: ... Node(double, double, std::vector<double>&) throw (WrongBoundsException); ... }; #endif // InternalNode.h #ifndef INTERNALNODE_H #define INTERNALNODE_H #include <vector> #include "Node.h" class InternalNode : public Node { public: // the position of the leftmost child (child left) int left_child; // the position of the parent int parent; InternalNode(double, double, std::vector<double>&, int parent, int left_child) throw (WrongBoundsException); private: int abcd; }; #endif // InternalNode.cpp #include "InternalNode.h" #define UNDEFINED_CHILD -1 #define ROOT -1 // Here is the problem InternalNode::InternalNode(double a, double b, std::vector<double> &v, int par, int lc) throw (WrongBoundsException) : Node(a, b, v), parent(par), left_child(lc) { std::cout << par << std::endl; } I get: $ g++ InternalNode.cpp InternalNode.cpp:16: error: declaration of ‘InternalNode::InternalNode(double, double, std::vector &, int, int) throw (WrongBoundsException)’ throws different exceptions InternalNode.h:17: error: from previous declaration ‘InternalNode::InternalNode(double, double, std::vector &, int, int)’ UPDATE 0: Fixed missing : UPDATE 1: Fixed throw exception

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  • StackOverflow Error at java.util.AbstractColllection.<init>(Unknown Source)

    - by thebulge
    I fixed my prior problem yesterday by just separating all the classes into separate files. Nevertheless, I wrote all the code down and seeing no errors was able to compile the program. Or so I thought. Here's the error code: Exception in thread "main" java.lang.StackOverflowError at java.util.AbstractCollection.<init>(Unknown Source) at java.util.AbstractList.<init>(Unknown Source) at java.util.Vector.<init>(Unknown Source) at java.util.Vector.<init>(Unknown Source) at java.util.Vector.<init>(Unknown Source Here are the spots where my I get the errors(marked with problem?) public class GameWorld implements IObservable, IGameWorld { // create collections class public Vector<GameObject> GameObjectList = new Vector<GameObject>(); // PROBLEM private Vector<IObserver> ObserverList = new Vector<IObserver>(); // declare objects Tank pTank = new Tank(10, 10); // other objects and variables to declare public GameWorld() { // add objects to GameObjectList } // accessors/mutators } I get another error here public class Tank extends Movable implements ISteerable { private int armorStrength; private int missileCount; public Tank() {} public Tank(int armStr, int misslCt) // problem? { armorStrength = armStr; // default armorStrength missileCount = misslCt; // default missileCount } public void setDirection(int direction) { this.setDirection(direction); // get input from left turn or right turn // updateValues(); } // access/mutators here I'm stumped on what to do here.

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  • Computing the scalar product of two vectors in C++

    - by HowardRoark
    I am trying to write a program with a function double_product(vector<double> a, vector<double> b) that computes the scalar product of two vectors. The scalar product is $a_{0}b_{0}+a_{1}b_{1}+...+a_{n-1}b_{n-1}$. Here is what I have. It is a mess, but I am trying! #include <iostream> #include <vector> using namespace std; class Scalar_product { public: Scalar_product(vector<double> a, vector<double> b); }; double scalar_product(vector<double> a, vector<double> b) { double product = 0; for (int i = 0; i <= a.size()-1; i++) for (int i = 0; i <= b.size()-1; i++) product = product + (a[i])*(b[i]); return product; } int main() { cout << product << endl; return 0; }

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  • C++: how serialize/deserialize objects without any library?

    - by Winte Winte
    I try to understand how serializing/deserializing works in c++, so I want to do that without any libs. But I really stuck with that. I start with simple objects but when I try to deserilize a vector I understand that I can't get a vector without if I don't write it size before. Moreover, I don't know which format of file I should choose because if digits will be existed before size of vector I haven't chance to read it right. However it is only the vector but I also want to do that with classes and map container. My task is serialize/deserialize a objects as this: PersonInfo { unsigned int age_; string name_; enum { undef, man, woman } sex_; } Person : PersonInfo { vector<Person> children_; map<string, PersonInfo> addrBook_; } Currently I know how to serialize simple objects in way as this: vector<PersonInfo> vecPersonInfo; vecPersonInfo.push_back(*personInfo); vecPersonInfo.push_back(*oneMorePersonInfo); ofstream file("file", ios::out | ios::binary); if (!file) { cout<<"can not open file"; } else { vector<PersonInfo>::const_iterator iterator = vecPersonInfo.begin(); for (; iterator != vecPersonInfo.end(); iterator++) { file<<*iterator; } Could you please suggest how I can do this for this conplex object or a good tutorial that explain it clearly?

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  • c++ queue template

    - by Dalton Conley
    ALright, pardon my messy code please. Below is my queue class. #include <iostream> using namespace std; #ifndef QUEUE #define QUEUE /*---------------------------------------------------------------------------- Student Class # Methods # Student() // default constructor Student(string, int) // constructor display() // out puts a student # Data Members # Name // string name Id // int id ----------------------------------------------------------------------------*/ class Student { public: Student() { } Student(string iname, int iid) { name = iname; id = iid; } void display(ostream &out) const { out << "Student Name: " << name << "\tStudent Id: " << id << "\tAddress: " << this << endl; } private: string name; int id; }; // define a typedef of a pointer to a student. typedef Student * StudentPointer; template <typename T> class Queue { public: /*------------------------------------------------------------------------ Queue Default Constructor Preconditions: none Postconditions: assigns default values for front and back to 0 description: constructs a default empty Queue. ------------------------------------------------------------------------*/ Queue() : myFront(0), myBack(0) {} /*------------------------------------------------------------------------ Copy Constructor Preconditions: requres a reference to a value for which you are copying Postconditions: assigns a copy to the parent Queue. description: Copys a queue and assigns it to the parent Queue. ------------------------------------------------------------------------*/ Queue(const T & q) { myFront = myBack = 0; if(!q.empty()) { // copy the first node myFront = myBack = new Node(q.front()); NodePointer qPtr = q.myFront->next; while(qPtr != NULL) { myBack->next = new Node(qPtr->data); myBack = myBack->next; qPtr = qPtr->next; } } } /*------------------------------------------------------------------------ Destructor Preconditions: none Postconditions: deallocates the dynamic memory for the Queue description: deletes the memory stored for a Queue. ------------------------------------------------------------------------*/ ~Queue() { NodePointer prev = myFront, ptr; while(prev != NULL) { ptr = prev->next; delete prev; prev = ptr; } } /*------------------------------------------------------------------------ Empty() Preconditions: none Postconditions: returns a boolean value. description: returns true/false based on if the queue is empty or full. ------------------------------------------------------------------------*/ bool empty() const { return (myFront == NULL); } /*------------------------------------------------------------------------ Enqueue Preconditions: requires a constant reference Postconditions: allocates memory and appends a value at the end of a queue description: ------------------------------------------------------------------------*/ void enqueue(const T & value) { NodePointer newNodePtr = new Node(value); if(empty()) { myFront = myBack = newNodePtr; newNodePtr->next = NULL; } else { myBack->next = newNodePtr; myBack = newNodePtr; newNodePtr->next = NULL; } } /*------------------------------------------------------------------------ Display Preconditions: requires a reference of type ostream Postconditions: returns the ostream value (for chaining) description: outputs the contents of a queue. ------------------------------------------------------------------------*/ void display(ostream & out) const { NodePointer ptr; ptr = myFront; while(ptr != NULL) { out << ptr->data << " "; ptr = ptr->next; } out << endl; } /*------------------------------------------------------------------------ Front Preconditions: none Postconditions: returns a value of type T description: returns the first value in the parent Queue. ------------------------------------------------------------------------*/ T front() const { if ( !empty() ) return (myFront->data); else { cerr << "*** Queue is empty -- returning garbage value ***\n"; T * temp = new(T); T garbage = * temp; delete temp; return garbage; } } /*------------------------------------------------------------------------ Dequeue Preconditions: none Postconditions: removes the first value in a queue ------------------------------------------------------------------------*/ void dequeue() { if ( !empty() ) { NodePointer ptr = myFront; myFront = myFront->next; delete ptr; if(myFront == NULL) myBack = NULL; } else { cerr << "*** Queue is empty -- " "can't remove a value ***\n"; exit(1); } } /*------------------------------------------------------------------------ pverloaded = operator Preconditions: requires a constant reference Postconditions: returns a const type T description: this allows assigning of queues to queues ------------------------------------------------------------------------*/ Queue<T> & operator=(const T &q) { // make sure we arent reassigning ourself // e.g. thisQueue = thisQueue. if(this != &q) { this->~Queue(); if(q.empty()) { myFront = myBack = NULL; } else { myFront = myBack = new Node(q.front()); NodePointer qPtr = q.myFront->next; while(qPtr != NULL) { myBack->next = new Node(qPtr->data); myBack = myBack->next; qPtr = qPtr->next; } } } return *this; } private: class Node { public: T data; Node * next; Node(T value, Node * first = 0) : data(value), next(first) {} }; typedef Node * NodePointer; NodePointer myFront, myBack, queueSize; }; /*------------------------------------------------------------------------ join Preconditions: requires 2 queue values Postconditions: appends queue2 to the end of queue1 description: this function joins 2 queues into 1. ------------------------------------------------------------------------*/ template <typename T> Queue<T> join(Queue<T> q1, Queue<T> q2) { Queue<T> q1Copy(q1), q2Copy(q2); Queue<T> jQueue; while(!q1Copy.empty()) { jQueue.enqueue(q1Copy.front()); q1Copy.dequeue(); } while(!q2Copy.empty()) { jQueue.enqueue(q2Copy.front()); q2Copy.dequeue(); } cout << jQueue << endl; return jQueue; } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a Queue of type T Postconditions: returns the ostream (for chaining) description: this function is overloaded for outputing a queue with << ----------------------------------------------------------------------------*/ template <typename T> ostream & operator<<(ostream &out, Queue<T> &s) { s.display(out); return out; } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a reference of type Student Postconditions: none description: this function is overloaded for outputing an object of type Student. ----------------------------------------------------------------------------*/ ostream & operator<<(ostream &out, Student &s) { s.display(out); } /*---------------------------------------------------------------------------- Overloaded << operator Preconditions: requires a constant reference and a reference of a pointer to a Student object. Postconditions: none description: this function is overloaded for outputing pointers to Students ----------------------------------------------------------------------------*/ ostream & operator<<(ostream &out, StudentPointer &s) { s->display(out); } #endif Now I'm having some issues with it. For one, when I add 0 to a queue and then I output the queue like so.. Queue<double> qdub; qdub.enqueue(0); cout << qdub << endl; That works, it will output 0. But for example, if I modify that queue in any way.. like.. assign it to a different queue.. Queue<double> qdub1; Queue<double> qdub2; qdub1.enqueue(0; qdub2 = qdub1; cout << qdub2 << endl; It will give me weird values for 0 like.. 7.86914e-316. Help on this would be much appreciated!

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  • Array of pointers in C++.

    - by Theorem
    I am not understanding the output of this , #include <iostream> using namespace std; // pointers and arrays char ch1 = 'a' , ch2= 'b'; char ch3[6] = {'c', 'd', 'e', 'f', 'g' , 'h'}; char *ptr[3]; int main () { ptr[0] = &ch1 ; ptr[2] = ch3; cout << &ch1 << endl; } The out put is abcdefgh . isn't &ch1 supposed to give the address of ch1 ? I cannot make sense why the output should be abcdefgh.

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  • Binary Cosine Cofficient

    - by hairyyak
    I was given the following forumulae for calculating this sim=|QnD| / v|Q|v|D| I went ahed and implemented a class to compare strings consisting of a series of words #pragma once #include <vector> #include <string> #include <iostream> #include <vector> using namespace std; class StringSet { public: StringSet(void); StringSet( const string the_strings[], const int no_of_strings); ~StringSet(void); StringSet( const vector<string> the_strings); void add_string( const string the_string); bool remove_string( const string the_string); void clear_set(void); int no_of_strings(void) const; friend ostream& operator <<(ostream& outs, StringSet& the_strings); friend StringSet operator *(const StringSet& first, const StringSet& second); friend StringSet operator +(const StringSet& first, const StringSet& second); double binary_coefficient( const StringSet& the_second_set); private: vector<string> set; }; #include "StdAfx.h" #include "StringSet.h" #include <iterator> #include <algorithm> #include <stdexcept> #include <iostream> #include <cmath> StringSet::StringSet(void) { } StringSet::~StringSet(void) { } StringSet::StringSet( const vector<string> the_strings) { set = the_strings; } StringSet::StringSet( const string the_strings[], const int no_of_strings) { copy( the_strings, &the_strings[no_of_strings], back_inserter(set)); } void StringSet::add_string( const string the_string) { try { if( find( set.begin(), set.end(), the_string) == set.end()) { set.push_back(the_string); } else { //String is already in the set. throw domain_error("String is already in the set"); } } catch( domain_error e) { cout << e.what(); exit(1); } } bool StringSet::remove_string( const string the_string) { //Found the occurrence of the string. return it an iterator pointing to it. vector<string>::iterator iter; if( ( iter = find( set.begin(), set.end(), the_string) ) != set.end()) { set.erase(iter); return true; } return false; } void StringSet::clear_set(void) { set.clear(); } int StringSet::no_of_strings(void) const { return set.size(); } ostream& operator <<(ostream& outs, StringSet& the_strings) { vector<string>::const_iterator const_iter = the_strings.set.begin(); for( ; const_iter != the_strings.set.end(); const_iter++) { cout << *const_iter << " "; } cout << endl; return outs; } //This function returns the union of the two string sets. StringSet operator *(const StringSet& first, const StringSet& second) { vector<string> new_string_set; new_string_set = first.set; for( unsigned int i = 0; i < second.set.size(); i++) { vector<string>::const_iterator const_iter = find(new_string_set.begin(), new_string_set.end(), second.set[i]); //String is new - include it. if( const_iter == new_string_set.end() ) { new_string_set.push_back(second.set[i]); } } StringSet the_set(new_string_set); return the_set; } //This method returns the intersection of the two string sets. StringSet operator +(const StringSet& first, const StringSet& second) { //For each string in the first string look though the second and see if //there is a matching pair, in which case include the string in the set. vector<string> new_string_set; vector<string>::const_iterator const_iter = first.set.begin(); for ( ; const_iter != first.set.end(); ++const_iter) { //Then search through the entire second string to see if //there is a duplicate. vector<string>::const_iterator const_iter2 = second.set.begin(); for( ; const_iter2 != second.set.end(); const_iter2++) { if( *const_iter == *const_iter2 ) { new_string_set.push_back(*const_iter); } } } StringSet new_set(new_string_set); return new_set; } double StringSet::binary_coefficient( const StringSet& the_second_set) { double coefficient; StringSet intersection = the_second_set + set; coefficient = intersection.no_of_strings() / sqrt((double) no_of_strings()) * sqrt((double)the_second_set.no_of_strings()); return coefficient; } However when I try and calculate the coefficient using the following main function: // Exercise13.cpp : main project file. #include "stdafx.h" #include <boost/regex.hpp> #include "StringSet.h" using namespace System; using namespace System::Runtime::InteropServices; using namespace boost; //This function takes as input a string, which //is then broken down into a series of words //where the punctuaction is ignored. StringSet break_string( const string the_string) { regex re; cmatch matches; StringSet words; string search_pattern = "\\b(\\w)+\\b"; try { // Assign the regular expression for parsing. re = search_pattern; } catch( regex_error& e) { cout << search_pattern << " is not a valid regular expression: \"" << e.what() << "\"" << endl; exit(1); } sregex_token_iterator p(the_string.begin(), the_string.end(), re, 0); sregex_token_iterator end; for( ; p != end; ++p) { string new_string(p->first, p->second); String^ copy_han = gcnew String(new_string.c_str()); String^ copy_han2 = copy_han->ToLower(); char* str2 = (char*)(void*)Marshal::StringToHGlobalAnsi(copy_han2); string new_string2(str2); words.add_string(new_string2); } return words; } int main(array<System::String ^> ^args) { StringSet words = break_string("Here is a string, with some; words"); StringSet words2 = break_string("There is another string,"); cout << words.binary_coefficient(words2); return 0; } I get an index which is 1.5116 rather than a value from 0 to 1. Does anybody have a clue why this is the case? Any help would be appreciated.

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  • Trouble passing a template function as an argument to another function in C++

    - by Darel
    Source of the problem -Accelerated C++, problem 8-5 I've written a small program that examines lines of string input, and tallies the number of times a word appears on a given line. The following code accomplishes this: #include <map> #include <iostream> #include <string> #include <vector> #include <list> #include <cctype> #include <iterator> using std::vector; using std::string; using std::cin; using std::cout; using std::endl; using std::getline; using std::istream; using std::string; using std::list; using std::map; using std::isspace; using std::ostream_iterator; using std::allocator; inline void keep_window_open() { cin.clear(); cout << "Please enter EOF to exit\n"; char ch; cin >> ch; return; } template <class Out> void split(const string& s, Out os) { vector<string> ret; typedef string::size_type string_size; string_size i = 0; // invariant: we have processed characters `['original value of `i', `i)' while (i != s.size()) { // ignore leading blanks // invariant: characters in range `['original `i', current `i)' are all spaces while (i != s.size() && isspace(s[i])) ++i; // find end of next word string_size j = i; // invariant: none of the characters in range `['original `j', current `j)' is a space while (j != s.size() && !isspace(s[j])) ++j; // if we found some nonwhitespace characters if (i != j) { // copy from `s' starting at `i' and taking `j' `\-' `i' chars *os++ = (s.substr(i, j - i)); i = j; } } } // find all the lines that refer to each word in the input map<string, vector<int> > xref(istream& in) // works // now try to pass the template function as an argument to function - what do i put for templated type? //map<string, vector<int> > xref(istream& in, void find_words(vector<string, typedef Out) = split) #LINE 1# { string line; int line_number = 0; map<string, vector<int> > ret; // read the next line while (getline(in, line)) { ++line_number; // break the input line into words vector<string> words; // works // #LINE 2# split(line, back_inserter(words)); // #LINE 3# //find_words(line, back_inserter(words)); // #LINE 4# attempting to use find_words as an argument to function // remember that each word occurs on the current line for (vector<string>::const_iterator it = words.begin(); it != words.end(); ++it) ret[*it].push_back(line_number); } return ret; } int main() { cout << endl << "Enter lines of text, followed by EOF (^Z):" << endl; // call `xref' using `split' by default map<string, vector<int> > ret = xref(cin); // write the results for (map<string, vector<int> >::const_iterator it = ret.begin(); it != ret.end(); ++it) { // write the word cout << it->first << " occurs on line(s): "; // followed by one or more line numbers vector<int>::const_iterator line_it = it->second.begin(); cout << *line_it; // write the first line number ++line_it; // write the rest of the line numbers, if any while (line_it != it->second.end()) { cout << ", " << *line_it; ++line_it; } // write a new line to separate each word from the next cout << endl; } keep_window_open(); return 0; } As you can see, the split function is a template function to handle various types of output iterators as desired. My problem comes when I try to generalize the xref function by passing in the templated split function as an argument. I can't seem to get the type correct. So my question is, can you pass a template function to another function as an argument, and if so, do you have to declare all types before passing it? Or can the compiler infer the types from the way the templated function is used in the body? To demonstrate the errors I get, comment out the existing xref function header, and uncomment the alternate header I'm trying to get working (just below the following commment line.) Also comment the lines tagged LINE 2 and LINE 3 and uncomment LINE 4, which is attempting to use the argument find_words (which defaults to split.) Thanks for any feedback!

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  • Convert string from getline into a number

    - by haskellguy
    I am trying to create a 2D array with vectors. I have a file that has for each line a set of numbers. So what I did I implemented a split function that every time I have a new number (separated by \t) it splits that and add it to the vector vector<double> &split(const string &s, char delim, vector<double> &elems) { stringstream ss(s); string item; while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; elems.push_back(number); } return elems; } vector<double> split(const string &s, char delim) { vector<double> elems; split(s, delim, elems); return elems; } After that I simply iterate through it. int main() { ifstream file("./data/file.txt"); string row; vector< vector<double> > matrix; int line_count = -1; while (getline(file, row)) { line_count++; if (line_count <= 4) continue; vector<double> cols = split(row, '\t'); matrix.push_back(cols); } ... } Now my issues is in this bit here: while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; Where item.c_str() is converted to a 0. Shouldn't that be still a string having the same value as item? It works on a separate example if I do straight from string to c_string, but when I use this getline I end up in this error situation, hints?

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  • how to fast compute distance between high dimension vectors

    - by chyojn
    assume there are three group of high dimension vectors: {a_1, a_2, ..., a_N}, {b_1, b_2, ... , b_N}, {c_1, c_2, ..., c_N}. each of my vector can be represented as: x = a_i + b_j + c_k, where 1 <=i, j, k <= N. then the vector is encoded as (i, j, k) wich is then can be decoded as x = a_i + b_j + c_k. my question is, if there are two vector: x = (i_1, j_1, k_1), y = (i_2, j_2, k_2), is there a method to compute the euclidian distance of these two vector without decode x and y.

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  • My IDE is showing "undeclared FileNotFoundException must be caught or thrown"

    - by Dan Czarnecki
    I am having the following issue above. I have tried actually putting a try-catch statement into the code as you will see below, but I can't get the compiler to get past that. import java.io.*; public class DirectoryStatistics extends DirectorySize { /* Dan Czarnecki October 24, 2013 Class variables: private File directory A File object that holds the pathname of the directory to look in private long sizeInBytes A variable of type long that holds the size of a file/directory (in bytes) private long fileCount A variable of type long that holds the number of files in a directory Constructors: public DirectoryStatistics(File startingDirectory) throws FileNotFoundException Creates a DirectoryStatistics object, given a pathname (inherited from DirectorySize class), and has 3 instance variables that hold the directory to search in, the size of each file (in bytes), and the number of files within the directory Modification history: October 24, 2013 Original version of class */ private File directory; private long sizeInBytes; private long fileCount; public DirectoryStatistics(File startingDirectory) throws FileNotFoundException { super(startingDirectory); try { if(directory == null) { throw new IllegalArgumentException("null input"); } if(directory.isDirectory() == false) { throw new FileNotFoundException("the following input is not a directory!"); } } catch(IOException ioe) { System.out.println("You have not entered a directory. Please try again."); } } public File getDirectory() { return this.directory; } public long getSizeInBytes() { return this.sizeInBytes; } public long getFileCount() { return this.fileCount; } public long setFileCount(long size) { fileCount = size; return size; } public long setSizeInBytes(long size) { sizeInBytes = size; return size; } public void incrementFileCount() { fileCount = fileCount + 1; } public void addToSizeInBytes(long addend) { sizeInBytes = sizeInBytes + addend; } public String toString() { return "Directory" + this.directory + "Size (in bytes) " + this.sizeInBytes + "Number of files: " + this.fileCount; } public int hashCode() { return this.directory.hashCode(); } public boolean equals(DirectoryStatistics other) { return this.equals(other); } } import java.io.*; import java.util.*; public class DirectorySize extends DirectoryProcessor { /* Dan Czarnecki October 17, 2013 Class variables: private Vector<Long> directorySizeList Variable of type Vector<Long> that holds the total file size of files in that directory as well as files within folders of that directory private Vector<File> currentFile Variable of type Vector<File> that holds the parent directory Constructors: public DirectorySize(File startingDirectory) throws FileNotFoundException Creates a DirectorySize object, takes in a pathname (inherited from DirectoryProcessor class, and has a single vector of a DirectoryStatistics object to hold the files and folders within a directory Modification History October 17, 2013 Original version of class Implemented run() and processFile() methods */ private Vector<DirectoryStatistics> directory; /* private Vector<Long> directorySizeList; private Vector<File> currentFile; */ public DirectorySize(File startingDirectory) throws FileNotFoundException { super(startingDirectory); directory = new Vector<DirectoryStatistics>(); } public void processFile(File file) { DirectoryStatistics parent; int index; File parentFile; System.out.println(file.getName()); System.out.println(file.getParent()); parentFile = file.getParentFile(); parent = new DirectoryStatistics(parentFile); System.out.println(parent); parent.equals(parent); index = directory.indexOf(parent); if(index == 0) { directory.elementAt(index).addToSizeInBytes(file.length()); directory.elementAt(index).incrementFileCount(); } if(index < 0) { directory.addElement(parent); directory.lastElement().setSizeInBytes(file.length()); directory.lastElement().incrementFileCount(); } Could someone tell me why I'm getting this issue?

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  • Context migration in CUDA.NET

    - by Vyacheslav
    I'm currently using CUDA.NET library by GASS. I need to initialize cuda arrays (actually cublas vectors, but it doesn't matters) in one CPU thread and use them in other CPU thread. But CUDA context which holding all initialized arrays and loaded functions, can be attached to only one CPU thread. There is mechanism called context migration API to detach context from one thread and attach it to another. But i don't how to properly use it in CUDA.NET. I tried something like this: class Program { private static float[] vector1, vector2; private static CUDA cuda; private static CUBLAS cublas; private static CUdeviceptr ptr; static void Main(string[] args) { cuda = new CUDA(false); cublas = new CUBLAS(cuda); cuda.Init(); cuda.CreateContext(0); AllocateVectors(); cuda.DetachContext(); CUcontext context = cuda.PopCurrentContext(); GetVectorFromDeviceAsync(context); } private static void AllocateVectors() { vector1 = new float[]{1f, 2f, 3f, 4f, 5f}; ptr = cublas.Allocate(vector1.Length, sizeof (float)); cublas.SetVector(vector1, ptr); vector2 = new float[5]; } private static void GetVectorFromDevice(object objContext) { CUcontext localContext = (CUcontext) objContext; cuda.PushCurrentContext(localContext); cuda.AttachContext(localContext); //change vector somehow vector1[0] = -1; //copy changed vector to device cublas.SetVector(vector1, ptr); cublas.GetVector(ptr, vector2); CUDADriver.cuCtxPopCurrent(ref localContext); } private static void GetVectorFromDeviceAsync(CUcontext cUcontext) { Thread thread = new Thread(GetVectorFromDevice); thread.IsBackground = false; thread.Start(cUcontext); } } But execution fails on attempt to copy changed vector to device because context is not attached? Any ideas how i can get it work?

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  • iphone compass tilt compensation

    - by m01d
    hi, has anybody already programmed a iphone compass heading tilt compensation? i have got some approaches, but some help or a better solution would be cool! FIRST i define a vector Ev, calculated out of the cross product of Gv and Hv. Gv is a gravity vector i build out of the accelerometer values and Hv is an heading vector built out the magnetometer values. Ev stands perpendicular on Gv and Hv, so it is heading to horizonatl East. SECOND i define a vector Rv, calculated out of the cross product Bv and Gv. Bv is my looking vector and it is defined as [0,0,-1]. Rv is perpendicular to Gv and Bv and shows always to the right. THIRD the angle between these two vectors, Ev and Rv, should be my corrected heading. to calculate the angle i build the dot product and thereof the arcos. phi = arcos ( Ev * Rv / |Ev| * |Rv| ) Theoretically it should work, but maybe i have to normalize the vectors?! Has anybody got a solution for this? Thanks, m01d

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  • boost bind callback function pointer as a parameter

    - by Takashi-kun
    I am trying to pass a function pointer using boost::bind. void Class::ThreadFunction(Type(*callbackFunc)(message_type::ptr&)) { } boost::shared_ptr<boost::thread> Class::Init(Type(*callbackFunc)(message_type::ptr&)) { return boost::shared_ptr<boost::thread> ( new boost::thread(boost::bind(&Class::ThreadFunction, callbackFunc)) ); } I get the following errors: 1>C:\dev\sapphire\boost_1_46_1\boost/bind/mem_fn.hpp(362) : warning C4180: qualifier applied to function type has no meaning; ignored 1>C:\dev\sapphire\boost_1_46_1\boost/bind/mem_fn.hpp(333) : error C2296: '->*' : illegal, left operand has type 'Type (__cdecl **)(message_type::ptr &)' However, I was able to change to the following, it works fine: void ThreadFunction(Type(*callbackFunc)(message_type::ptr&)) { } boost::shared_ptr<boost::thread> Class::Init(Type(*callbackFunc)(message_type::ptr&)) { return boost::shared_ptr<boost::thread> ( new boost::thread(boost::bind(&ThreadFunction, callbackFunc)) ); } Why do I get those errors if I declare the method in the Class class?

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  • How do I reorder vector data using ARM Neon intrinsics?

    - by goldenmean
    This is specifically related to ARM Neon SIMD coding. I am using ARM Neon instrinsics for certain module in a video decoder. I have a vectorized data as follows: There are four 32 bit elements in a Neon register - say, Q0 - which is of size 128 bit. 3B 3A 1B 1A There are another four, 32 bit elements in other Neon register say Q1 which is of size 128 bit. 3D 3C 1D 1C I want the final data to be in order as shown below: 1D 1C 1B 1A 3D 3C 3D 3A What Neon instrinsics can achieve the desired data order?

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  • How do i a vector data using ARM Neon intrinsics?

    - by goldenmean
    Hello, This is specifically related to ARM Neon SIMD coding.I am using ARM Neon instrinsics for certain module in a Video Decoder. I have a vectorized data as follows:- There are four, 32 bit elements in a Neon register say Q0 which is of size 128 bit. 3B 3A 1B 1A There are another four, 32 bit elements in other Neon register say Q1 which is of size 128 bit. 3D 3C 1D 1C I want the final data to be in order as shown below:- 1D 1C 1B 1A 3D 3C 3D 3A Using what Neon instrinscis can achive the desired data order? thanks, -AD

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  • Delay On Assembler?

    - by Norm
    Hey, I want to know how i can do delay (Timer) on assembler 16 bit on PC. Thank You for helping, Norm. OS: Windows CODE: delay: inc bx cmp bx,WORD ptr[time] je delay2 jmp delay delay2: inc dx cmp dx,WORD ptr[time2] je delay3 jmp delay mov bx,0 delay3: inc cx cmp cx,WORD ptr[time3] je Finish_delay jmp delay its not work good i need less complicated code

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  • GCC emits extra code for boost::shared_ptr dereference

    - by Checkers
    I have the following code: #include <boost/shared_ptr.hpp> struct Foo { int a; }; static int A; void func_shared(const boost::shared_ptr<Foo> &foo) { A = foo->a; } void func_raw(Foo * const foo) { A = foo->a; } I thought the compiler would create identical code, but for shared_ptr version an extra seemingly redundant instruction is emitted. Disassembly of section .text: 00000000 <func_raw(Foo*)>: 0: 55 push ebp 1: 89 e5 mov ebp,esp 3: 8b 45 08 mov eax,DWORD PTR [ebp+8] 6: 5d pop ebp 7: 8b 00 mov eax,DWORD PTR [eax] 9: a3 00 00 00 00 mov ds:0x0,eax e: c3 ret f: 90 nop 00000010 <func_shared(boost::shared_ptr<Foo> const&)>: 10: 55 push ebp 11: 89 e5 mov ebp,esp 13: 8b 45 08 mov eax,DWORD PTR [ebp+8] 16: 5d pop ebp 17: 8b 00 mov eax,DWORD PTR [eax] 19: 8b 00 mov eax,DWORD PTR [eax] 1b: a3 00 00 00 00 mov ds:0x0,eax 20: c3 ret I'm just curious, is this necessary, or it is just an optimizer's shortcoming? Compiling with g++ 4.1.2, -O3 -NDEBUG.

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  • Call a void* as a function without declaring a function pointer

    - by ToxIk
    I've searched but couldn't find any results (my terminology may be off) so forgive me if this has been asked before. I was wondering if there is an easy way to call a void* as a function in C without first declaring a function pointer and then assigning the function pointer the address; ie. assuming the function to be called is type void(void) void *ptr; ptr = <some address>; ((void*())ptr)(); /* call ptr as function here */ with the above code, I get error C2066: cast to function type is illegal in VC2008 If this is possible, how would the syntax differ for functions with return types and multiple parameters?

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  • array of pointers

    - by tushar
    char *a[]={"diamonds","clubs","spades","hearts"}; char **p[]={a+3,a+2,a+1,a}; char ***ptr=p; cout<<*ptr[2][2]; why does it display h and please explain how is the 2d array of ptr implementing and its elements

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  • How should I manage data in an 2D vector based animation program?

    - by shadow
    I've been trying to design a program that makes 2D animations and then uses the ffmpeg library to create the video for possible use in tv and movies. The problem is when I think about how to manage the data in the application I can only think of two ways, I don't think either of them will work out very well. One is to use an SQlite database, but it seems like it will be difficult to save, especially if an artist puts 1000 things on screen. The other is to use something like linked lists, which would duplicate many features of the database and get complicated when dealing with things like points on a bezier curve and jumping to a frame and collecting all the objects that need to be drawn on that frame. Should I use one of these solutions, or is there something else that would be better? Currently planning to use C# for code.

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  • UTF-8 to Unicode conversion

    - by sandeep
    Hi, I am having problems with converting UTF-8 to Unicode. Below is the code: int charset_convert( char * string, char * to_string,char* charset_from, char* charset_to) { char *from_buf, *to_buf, *pointer; size_t inbytesleft, outbytesleft, ret; size_t TotalLen; iconv_t cd; if (!charset_from || !charset_to || !string) /* sanity check */ return -1; if (strlen(string) < 1) return 0; /* we are done, nothing to convert */ cd = iconv_open(charset_to, charset_from); /* Did I succeed in getting a conversion descriptor ? */ if (cd == (iconv_t)(-1)) { /* I guess not */ printf("Failed to convert string from %s to %s ", charset_from, charset_to); return -1; } from_buf = string; inbytesleft = strlen(string); /* allocate max sized buffer, assuming target encoding may be 4 byte unicode */ outbytesleft = inbytesleft *4 ; pointer = to_buf = (char *)malloc(outbytesleft); memset(to_buf,0,outbytesleft); memset(pointer,0,outbytesleft); ret = iconv(cd, &from_buf, &inbytesleft, &pointer, &outbytesleft);ing memcpy(to_string,to_buf,(pointer-to_buf); } main(): int main() { char UTF []= {'A', 'B'}; char Unicode[1024]= {0}; char* ptr; int x=0; iconv_t cd; charset_convert(UTF,Unicode,"UTF-8","UNICODE"); ptr = Unicode; while(*ptr != '\0') { printf("Unicode %x \n",*ptr); ptr++; } return 0; } It should give A and B but i am getting: ffffffff fffffffe 41 Thanks, Sandeep

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  • When does printf("%s", char*) stop printing?

    - by remagen
    In my class we are writing our own copy of C's malloc() function. To test my code (which can currently allocate space fine) I was using: char* ptr = my_malloc(6*sizeof(char)); memcpy(ptr, "Hello\n", 6*sizeof(char)); printf("%s", ptr); The output would typically be this: Hello Unprintable character Some debugging figured that my code wasn't causing this per say, as ptr's memory is as follows: [24 bytes of meta info][Number of requested bytes][Padding] So I figured that printf was reaching into the padding, which is just garbage. So I ran a test of: printf("%s", "test\nd"); and got: test d Which makes me wonder, when DOES printf("%s", char*) stop printing chars?

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  • Accessing structure elements using pointers

    - by Arun Nadesh
    Hi Everybody, Greetings! I got surprised when the following program did not crash. typedef struct _x{ int a; char b; int c; }x; main() { x *ptr=0; char *d=&ptr->b; } As per my understanding the -> operator has higher precedence over & operator. So I expected the program to crash at the below statement when we try to dereference the NULL pointer tr. char *d=&ptr->b; But the statement &ptr->b evaluates to a valid address. Could somebody please explain where I'm wrong? Thanks & Regards, Arun

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