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• Problem with operator ==

  - by CPPDev

  I am facing some problem with use of operator == in the following c++ program. #include < iostream> using namespace std; class A { public: A(char *b) { a = b; } A(A &c) { a = c.a; } bool operator ==(A &other) { return strcmp(a, other.a); } private: char *a; }; int main() { A obj("test"); A obj1("test1"); if(obj1 == A("test1")) { cout<<"This is true"<<endl; } } What's wrong with if(obj1 == A("test1")) line ?? Any help is appreciated.

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• Linker library for OpenMP for Snow Leopard?

  - by unknownthreat

  Currently, I am trying out OpenMP on XCode 3.2.2 on Snow Leopard: #include <omp.h> #include <iostream> #include <stdio.h> int main (int argc, char * const argv[]) { #pragma omp parallel printf("Hello from thread %d, nthreads %d\n", omp_get_thread_num(), omp_get_num_threads()); return 0; } I didn't include any linking libraries yet, so the linker complains: "_omp_get_thread_num", referenced from: _main in main.o "_omp_get_num_threads", referenced from: _main in main.o OK, fine, no problem, I take a look in the existing framework, looking for keywords such as openmp or omp... here comes the problem, where is the linking library? Or should I say, what is the name of the linking library for openMP? Is it dylib, framework or what? Or do I need to get it from somewhere first?

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• How *restrict / *__restrict__ works in C / C++?

  - by Moraru Lilian

  Here is some code I wrote: #include <iostream> using namespace std; int main(void) { int i = 7; int *__restrict__ a = &i; *a = 5; int *b = &i, *c = &i; *b = 8; *c = 9; cout << **&a << endl; //*a return 0; } From what I've read, if I do " *a = 5 ", it changes the value of the memory he, "a", is pointing to, after that the memory to which he is pointing to should not be modified by anyone else except "a", which means that these program is wrong because "b" and "c" modify it after that. Or, even if "b" modifies "i" first, after that only "a" should have access to that memory( "i" ). Am I getting it correctly?

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• VS 11 with std::future - Is this a bug?

  - by cooky451

  I recently installed the Visual Studio 11 Developer Preview. While playing with threads and futures, I came around this setup: #include <future> #include <iostream> int foo(unsigned a, unsigned b) { return 5; } int main() { std::future<int> f = std::async(foo, 5, 7); std::cout << f.get(); } So, very simple. But since there are two arguments for "foo", VS 11 doesn't want to compile it. (However, g++ does: http://ideone.com/ANrPj) (The runtime error is no problem: std::future exception on gcc experimental implementation of C++0x) (VS 11 errormessage: http://pastebin.com/F9Xunh2s) I'm a little confused right now, since this error seems extremely obvious to me, even if it is a developer preview. So my questions are: Is this code correct according to the C++11 standard? Is this bug already known/reported?

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• Unsigned long with negative value

  - by egiakoum1984

  Please see the simple code below: #include <iostream> #include <stdlib.h> using namespace std; int main(void) { unsigned long currentTrafficTypeValueDec; long input; input=63; currentTrafficTypeValueDec = (unsigned long) 1LL << input; cout << currentTrafficTypeValueDec << endl; printf("%u \n", currentTrafficTypeValueDec); printf("%ld \n", currentTrafficTypeValueDec); return 0; } Why printf() displays the currentTrafficTypeValueDec (unsigned long) with negative value? The output is: 9223372036854775808 0 -9223372036854775808

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• Inheriting and static members

  - by Bruce

  Here is my code - #include <iostream> #include <conio.h> using namespace std; class Base { public: int a; }; //int Base::a = 5; class Derived : public Base { public: int static a; }; int main() { Derived d; cout<<d.a; getch(); return 0; } I get a linker error here. But when I do it the other way round - class Base { public: int static a; }; int Base::a = 5; class Derived : public Base { public: int a; }; I get no error. Can someone please explain what is happening here.

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• g++ and c++0x specification support

  - by SepiDev

  although it's been said that the support for c++0x new features in g++ are in experimental mode, many gcc developer claimed that you can use most of the new features in your codes and get the program to work. but when I try to compile this simple program it results in segmentation fault. Why? #include <thread> #include <iostream> void my_thread_func() { std::cout<<"hello"<<std::endl; } int main() { std::thread t(my_thread_func); t.join(); } g++ -std=c++0x -Wall -o run main.cc

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• How does sizeof calculate the size of structures

  - by Gearoid Murphy

  I know that a char and an int are calculated as being 8 bytes on 32 bit architectures due to alignment, but I recently came across a situation where a structure with 3 shorts was reported as being 6 bytes by the sizeof operator. Code is as follows: #include <iostream> using namespace std ; struct IntAndChar { int a ; unsigned char b ; }; struct ThreeShorts { unsigned short a ; unsigned short b ; unsigned short c ; }; int main() { cout<<sizeof(IntAndChar)<<endl; // outputs '8' cout<<sizeof(ThreeShorts)<<endl; // outputs '6', I expected this to be '8' return 0 ; } Compiler : g++ (Debian 4.3.2-1.1) 4.3.2. This really puzzles me, why isn't alignment enforced for the structure containing 3 shorts?

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• Passing Text for command line

  - by Kasun

  Hi, I need to pass some text which is in richtext box to command line. This is my Button click even which start the cmd. private void button1_Click(object sender, EventArgs e) { ProcessStartInfo psi = new ProcessStartInfo { FileName = "cmd", Arguments = @"/k ""C:\Program Files\Microsoft Visual Studio 9.0\VC\bin\vcvars32.bat""", }; Process.Start(psi); } In my rich text box contain following text. include iostream using namespace std; int main() { cout << "Welcome to the wonderful world of C++!!!\n"; return 0; } Can anyone provide me necessary codes.

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• Make Map Key Sorted According To Insert Sequence

  - by Yan Cheng CHEOK

  Without help from additional container (like vector), is it possible that I can make map's key sorted same sequence as insertion sequence? #include <map> #include <iostream> using namespace std; int main() { map<const char*, int> m; m["c"] = 2; m["b"] = 2; m["a"] = 2; m["d"] = 2; for (map<const char*, int>::iterator begin = m.begin(); begin != m.end(); begin++) { // How can I get the loop sequence same as my insert sequence. // c, b, a, d std::cout << begin->first << std::endl; } getchar(); }

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• getline() returns empty line in Eclipse but working properly in Dev C++

  - by pocoa

  Here is my code: #include <iostream> #include <stdlib.h> #include <fstream> using namespace std; int main() { string line; ifstream inputFile; inputFile.open("input.txt"); do { getline(inputFile, line); cout << line << endl; } while (line != "0"); return 0; } input.txt content: 5 9 2 9 3 8 2 8 2 1 0 In Enclipse, it goes to infinite-loop. I'm using MinGW 5.1.6 + Eclipse CDT. I tried many things but I couldn't find the problem.

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• Why is .NET faster than C++ in this case?

  - by acidzombie24

  -edit- I LOVE SLaks comment. "The amount of misinformation in these answers is staggering." :D Calm down guys. Pretty much all of you were wrong. I DID make optimizations. It turns out whatever optimizations I made wasn't good enough. I ran the code in GCC using gettimeofday (I'll paste code below) and used g++ -O2 file.cpp and got slightly faster results then C#. Maybe MS didn't create the optimizations needed in this specific case but after downloading and installing mingw I was tested and found the speed to be near identical. Justicle Seems to be right. I could have sworn I use clock on my PC and used that to count and found it was slower but problem solved. C++ speed isn't almost twice as slower in the MS compiler. When my friend informed me of this I couldn't believe it. So I took his code and put some timers onto it. Instead of Boo I used C#. I constantly got faster results in C#. Why? The .NET version was nearly half the time no matter what number I used. C++ version: #include <iostream> #include <stdio.h> #include <intrin.h> #include <windows.h> using namespace std; int fib(int n) { if (n < 2) return n; return fib(n - 1) + fib(n - 2); } int main() { __int64 time = 0xFFFFFFFF; while (1) { int n; //cin >> n; n = 41; if (n < 0) break; __int64 start = __rdtsc(); int res = fib(n); __int64 end = __rdtsc(); cout << res << endl; cout << (float)(end-start)/1000000<<endl; break; } return 0; } C# version: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; using System.ComponentModel; using System.Threading; using System.IO; using System.Diagnostics; namespace fibCSTest { class Program { static int fib(int n) { if (n < 2)return n; return fib(n - 1) + fib(n - 2); } static void Main(string[] args) { //var sw = new Stopwatch(); //var timer = new PAB.HiPerfTimer(); var timer = new Stopwatch(); while (true) { int n; //cin >> n; n = 41; if (n < 0) break; timer.Start(); int res = fib(n); timer.Stop(); Console.WriteLine(res); Console.WriteLine(timer.ElapsedMilliseconds); break; } } } } GCC version: #include <iostream> #include <stdio.h> #include <sys/time.h> using namespace std; int fib(int n) { if (n < 2) return n; return fib(n - 1) + fib(n - 2); } int main() { timeval start, end; while (1) { int n; //cin >> n; n = 41; if (n < 0) break; gettimeofday(&start, 0); int res = fib(n); gettimeofday(&end, 0); int sec = end.tv_sec - start.tv_sec; int usec = end.tv_usec - start.tv_usec; cout << res << endl; cout << sec << " " << usec <<endl; break; } return 0; }

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• static array in c++ forgets its size

  - by Karel Bílek

  In this small example, c++ forgets size of an array, passed to a constructor. I guess it is something simple, but I cannot see it. In classes.h, there is this code: #ifndef CLASSES_INC #define CLASSES_INC #include <iostream> class static_class { public: static_class(int array[]) { std::cout<<sizeof(array)/sizeof(int)<<"\n"; } }; class my_class{ public: static static_class s; static int array[4]; }; #endif In classes.cpp, there is this code: #include "classes.h" int my_class::array[4]={1, 2, 3, 4}; static_class my_class::s = static_class(my_class::array); In main.cpp, there is only simple #include "classes.h" int main () { return 0; } Now, the desired output (from the constructor of static_class) is 4. But what I get is 1. Why is that?

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• C operating system createprozess

  - by Tyzak

  hello, i'm new at C Programming (i learned c++) i want to create a process with windows.h at first i just want to start my main programm that creates a process ( -- starts an other programm) that's my code, but it doesn't really work, i removed every unnessasery line of code but "void sleep(700)" (or "sleep (700)" for testing if the windows methods work, but i get an error, that "sleep" cant be found. #include <iostream> #include <windows.h> #include <string> using namespace std; void main() { //bool ret; //startupinfo stupinfo; //prozess_information pro2info; //Getstartupinfo (&stupinfo); //createprozess(null, "C:\\bsss10\\betriebssystemePRA1.exe", null, null, false, create_new_console, null, // null, &stupinfo, &pro2info); sleep (700); cout<< "hello"; } thanks in advance

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• In the following implementation of static_strlen, why are the & and parentheses around str necessary

  - by Ben

  If I change the type to const char str[Len], I get the following error: error: no matching function for call to ‘static_strlen(const char [5])’ Am I correct that static_strlen expects an array of const char references? My understanding is that arrays are passed as pointers anyway, so what need is there for the elements to be references? Or is that interpretation completely off-the-mark? #include <iostream> template <size_t Len> size_t static_strlen(const char (&str)[Len]) { return Len - 1; } int main() { std::cout << static_strlen("oyez") << std::endl; return 0; }

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• Undefined reference to ...

  - by Patrick LaChance

  I keep getting this error message every time I try to compile, and I cannot find out what the problem is. any help would be greatly appreciated: C:\DOCUME~1\Patrick\LOCALS~1\Temp/ccL92mj9.o:main.cpp:(.txt+0x184): undefined reference to 'List::List()' C:\DOCUME~1\Patrick\LOCALS~1\Temp/ccL92mj9.o:main.cpp:(.txt+0x184): undefined reference to 'List::add(int)' collect2: ld returned 1 exit status code: //List.h #ifndef LIST_H #define LIST_H #include <exception> //brief Definition of linked list class class List { public: /** \brief Exception for operating on empty list */ class Empty : public std::exception { public: virtual const char* what() const throw(); }; /** \brief Exception for invalid operations other than operating on an empty list */ class InvalidOperation : public std::exception { public: virtual const char* what() const throw(); }; /** \brief Node within List */ class Node { public: /** data element stored in this node */ int element; /** next node in list */ Node* next; /** previous node in list */ Node* previous; Node (int element); ~Node(); void print() const; void printDebug() const; }; List(); ~List(); void add(int element); void remove(int element); int first()const; int last()const; int removeFirst(); int removeLast(); bool isEmpty()const; int size()const; void printForward() const; void printReverse() const; void printDebug() const; /** enables extra output for debugging purposes */ static bool traceOn; private: /** head of list */ Node* head; /** tail of list */ Node* tail; /** count of number of nodes */ int count; }; #endif //List.cpp I only included the parts of List.cpp that might be the issue #include "List.h" #include <iostream> #include <iomanip> using namespace std; List::List() { //List::size = NULL; head = NULL; tail = NULL; } List::~List() { Node* current; while(head != NULL) { current = head-> next; delete current->previous; if (current->next!=NULL) { head = current; } else { delete current; } } } void List::add(int element) { Node* newNode; Node* current; newNode->element = element; if(newNode->element > head->element) { current = head->next; } else { head->previous = newNode; newNode->next = head; newNode->previous = NULL; return; } while(newNode->element > current->element) { current = current->next; } if(newNode->element <= current->element) { newNode->previous = current->previous; newNode->next = current; } } //main.cpp #include "List.h" #include <iostream> #include <string> using namespace std; //void add(int element); int main (char** argv, int argc) { List* MyList = new List(); bool quit = false; string value; int element; while(quit==false) { cin>>value; if(value == "add") { cin>>element; MyList->add(element); } if(value=="quit") { quit = true; } } return 0; } I'm doing everything I think I'm suppose to be doing. main.cpp isn't complete yet, just trying to get the add function to work first. Any help will be greatly appreciated.

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• Simple syntax error still eluding me.

  - by melee

  Here is the header for a class I started: #ifndef CANVAS_ #define CANVAS_ #include <iostream> #include <iomanip> #include <string> #include <stack> class Canvas { public: Canvas(); void Paint(int R, int C, char Color); const int Nrow; const int Ncol; string Title; int image[][100]; stack<int> path; struct PixelCoordinates { unsigned int r; unsigned int c; } position; Canvas operator<< (const Canvas& One ); Canvas operator>>( Canvas& One ); }; /*----------------------------------------------------------------------------- Name: operator<< Purpose: Put a Canvas into an output stream -----------------------------------------------------------------------------*/ ostream& operator<<( ostream& Out, const Canvas& One ) { Out << One.Title << endl; Out << "Rows: " << One.Nrow << " Columns: " << One.Ncol << endl; int i,j; for( i=0; i<One.Nrow; i++) { cout<<"\n\n\n"; cout<< " COLUMN\n"; cout<< " 1 2 3"; for(i=0;i<One.Nrow;i++) { cout<<"\nROW "<<i+1; for(j=0;j<One.Ncol;j++) cout<< One.image[i][j]; } } return Out; } /*----------------------------------------------------------------------------- Name: operator>> Purpose: Get a Canvas from an input stream -----------------------------------------------------------------------------*/ istream& operator>>( istream& In, Canvas& One ) { // string Line; // int Place = 0; // { // In >> Line; // if (In.good()) // { // One.image[Place][0] = Line; // Place++; // } // return In; #endif Here is my implementation file for class Canvas: using namespace std; #include <iostream> #include <iomanip> #include <string> #include <stack> #include "proj05.canvas.h" //----------------Constructor----------------// Canvas::Canvas() { Title = ""; Nrow = 0; Ncol = 0; image[][100] = {}; position.r = 0; position.c = 0; } //-------------------Paint------------------// void Canvas::Paint(int R, int C, char Color) { cout << "Paint to be implemented" << endl; } And the errors I'm getting are these: proj05.canvas.cpp: In function 'std::istream& operator>>(std::istream&, Canvas&)': proj05.canvas.cpp:11: error: expected `;' before '{' token proj05.canvas.cpp:24: error: expected `}' at end of input From my limited experience, they look like simple syntax errors but for the life of me, I cannot see what I am missing. I know putting a ; at the end of Canvas::Canvas() is wrong but that seems to be what it expects. Could someone please clarify for me? (Also, I know much of the code for the << and operator definitions look terrible, but unless that is the specific reason for the error please do not address it. This is a draft :) )

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• C++ Operator overloading - 'recreating the Vector'

  - by Wallter

  I am currently in a collage second level programing course... We are working on operator overloading... to do this we are to rebuild the vector class... I was building the class and found that most of it is based on the [] operator. When I was trying to implement the + operator I run into a weird error that my professor has not seen before (apparently since the class switched IDE's from MinGW to VS express...) (I am using Visual Studio Express 2008 C++ edition...) Vector.h #include <string> #include <iostream> using namespace std; #ifndef _VECTOR_H #define _VECTOR_H const int DEFAULT_VECTOR_SIZE = 5; class Vector { private: int * data; int size; int comp; public: inline Vector (int Comp = 5,int Size = 0) : comp(Comp), size(Size) { if (comp > 0) { data = new int [comp]; } else { data = new int [DEFAULT_VECTOR_SIZE]; comp = DEFAULT_VECTOR_SIZE; } } int size_ () const { return size; } int comp_ () const { return comp; } bool push_back (int); bool push_front (int); void expand (); void expand (int); void clear (); const string at (int); int operator[ ](int); Vector& operator+ (Vector&); Vector& operator- (const Vector&); bool operator== (const Vector&); bool operator!= (const Vector&); ~Vector() { delete [] data; } }; ostream& operator<< (ostream&, const Vector&); #endif Vector.cpp #include <iostream> #include <string> #include "Vector.h" using namespace std; const string Vector::at(int i) { this[i]; } void Vector::expand() { expand(size); } void Vector::expand(int n ) { int * newdata = new int [comp * 2]; if (*data != NULL) { for (int i = 0; i <= (comp); i++) { newdata[i] = data[i]; } newdata -= comp; comp += n; delete [] data; *data = *newdata; } else if ( *data == NULL || comp == 0) { data = new int [DEFAULT_VECTOR_SIZE]; comp = DEFAULT_VECTOR_SIZE; size = 0; } } bool Vector::push_back(int n) { if (comp = 0) { expand(); } for (int k = 0; k != 2; k++) { if ( size != comp ){ data[size] = n; size++; return true; } else { expand(); } } return false; } void Vector::clear() { delete [] data; comp = 0; size = 0; } int Vector::operator[] (int place) { return (data[place]); } Vector& Vector::operator+ (Vector& n) { int temp_int = 0; if (size > n.size_() || size == n.size_()) { temp_int = size; } else if (size < n.size_()) { temp_int = n.size_(); } Vector newone(temp_int); int temp_2_int = 0; for ( int j = 0; j <= temp_int && j <= n.size_() && j <= size; j++) { temp_2_int = n[j] + data[j]; newone[j] = temp_2_int; } //////////////////////////////////////////////////////////// return newone; //////////////////////////////////////////////////////////// } ostream& operator<< (ostream& out, const Vector& n) { for (int i = 0; i <= n.size_(); i++) { //////////////////////////////////////////////////////////// out << n[i] << " "; //////////////////////////////////////////////////////////// } return out; } Errors: out << n[i] << " "; error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const Vector' (or there is no acceptable conversion) return newone; error C2106: '=' : left operand must be l-value As stated above, I am a student going into Computer Science as my selected major I would appreciate tips, pointers, and better ways to do stuff :D

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• C++ 'ClassName Not Declared' Error

  - by Arjun Nayini

  I have this cpp file. dsets.cpp: #ifndef DSETS_CPP #define DSET_CPP //Adds elements to the DisjointSet data structure. This function adds //x unconnected roots to the end of the array. void DisjointSets::addelements(int x){ } //Given an int this function finds the root associated with that node. int DisjointSets::find(int x){ return 0; } //This function reorders the uptree in order to represent the union of two //subtrees void DisjointSets::setunion(int x, int y){ } #endif and this header file dsets.h: #ifndef DSETS_H #define DSET_H #include <iostream> #include <vector> using namespace std; class DisjointSets { public: void addelements(int x); int find(int x); void setunion(int x, int y); private: vector<int> x; }; #include "dsets.cpp" #endif And I keep getting an error that is saying that "DisjointSets has no been declared" ~ ~

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• C++ word to bytes

  - by Vit

  Hi, I tried to read CPUID using assembler in C++. I know there is function for it in , but I want the asm way. So, after CPUID is executed, it should fill eax,ebx,ecx registers with ASCII coded string. But my problem is, since I can in asm adress only full, or half eax register, how to break that 32 bits into 4 bytes. I used this: #include <iostream> #include <stdlib.h> int main() { _asm { cpuid /*There I need to mov values from eax,ebx and ecx to some propriate variables*/ } system("PAUSE"); return(0); }

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• c++ and c# speed compared

  - by Mack

  I was worried about C#'s speed when it deals with heavy calculations, when you need to use raw CPU power. I always thought that C++ is much faster than C# when it comes to calculations. So I did some quick tests. The first test computes prime numbers < an integer n, the second test computes some pandigital numbers. The idea for second test comes from here: Pandigital Numbers C# prime computation: using System; using System.Diagnostics; class Program { static int primes(int n) { uint i, j; int countprimes = 0; for (i = 1; i <= n; i++) { bool isprime = true; for (j = 2; j <= Math.Sqrt(i); j++) if ((i % j) == 0) { isprime = false; break; } if (isprime) countprimes++; } return countprimes; } static void Main(string[] args) { int n = int.Parse(Console.ReadLine()); Stopwatch sw = new Stopwatch(); sw.Start(); int res = primes(n); sw.Stop(); Console.WriteLine("I found {0} prime numbers between 0 and {1} in {2} msecs.", res, n, sw.ElapsedMilliseconds); Console.ReadKey(); } } C++ variant: #include <iostream> #include <ctime> int primes(unsigned long n) { unsigned long i, j; int countprimes = 0; for(i = 1; i <= n; i++) { int isprime = 1; for(j = 2; j < (i^(1/2)); j++) if(!(i%j)) { isprime = 0; break; } countprimes+= isprime; } return countprimes; } int main() { int n, res; cin>>n; unsigned int start = clock(); res = primes(n); int tprime = clock() - start; cout<<"\nI found "<<res<<" prime numbers between 1 and "<<n<<" in "<<tprime<<" msecs."; return 0; } When I ran the test trying to find primes < than 100,000, C# variant finished in 0.409 seconds and C++ variant in 5.553 seconds. When I ran them for 1,000,000 C# finished in 6.039 seconds and C++ in about 337 seconds. Pandigital test in C#: using System; using System.Diagnostics; class Program { static bool IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return false; } return digits == (1 << count) - 1; } static void Main() { int pans = 0; Stopwatch sw = new Stopwatch(); sw.Start(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } sw.Stop(); Console.WriteLine("{0}pcs, {1}ms", pans, sw.ElapsedMilliseconds); Console.ReadKey(); } } Pandigital test in C++: #include <iostream> #include <ctime> using namespace std; int IsPandigital(int n) { int digits = 0; int count = 0; int tmp; for (; n > 0; n /= 10, ++count) { if ((tmp = digits) == (digits |= 1 << (n - ((n / 10) * 10) - 1))) return 0; } return digits == (1 << count) - 1; } int main() { int pans = 0; unsigned int start = clock(); for (int i = 1; i <= 123456789; i++) { if (IsPandigital(i)) { pans++; } } int ptime = clock() - start; cout<<"\nPans:"<<pans<<" time:"<<ptime; return 0; } C# variant runs in 29.906 seconds and C++ in about 36.298 seconds. I didn't touch any compiler switches and bot C# and C++ programs were compiled with debug options. Before I attempted to run the test I was worried that C# will lag well behind C++, but now it seems that there is a pretty big speed difference in C# favor. Can anybody explain this? C# is jitted and C++ is compiled native so it's normal that a C++ will be faster than a C# variant. Thanks for the answers!

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• Selecting an area from displayed image using CImg library

  - by sravan

  hi all, i use CImg for my image processing work. I had written a small piece of code which is follows: #include "../CImg.h" #include <iostream> using namespace std; using namespace cimg_library; int main(int argc,char**argv) { CImg<int> img(argv[1]); CImgDisplay disp; disp.assign(img); while(!disp.is_closed) disp.wait(); return 0; } Now i want to select an area from the displayed image. Can some one tell me how to select an area from displayed image and store the selected pixels, and display the selected region in different display window. If some one can provide code, it will be of great help to me. Thank you all

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• Visual Studio 2005 - VC++ compiler C1001 on Windows 7

  - by Fritz H

  When I try to build a simple "Hello World" C++ app on Windows 7 Beta, using Visual Studio 2005 (VC++2005) I get a rather generic error C1001 error (Internal compiler error) The compiler seems to just crash, and Windows pops up its (un)helpful This program has stopped working dialog. The file it complains about is mcp1.cpp. Has anyone come across this before? Cheers, Fritz EDIT: The code is: #include <iostream> int main(int argc, char** argv) { std::cout << "Hello!"; return 0; } EDIT 2: I have installed SP1 as well as SP1 for Vista. VS popped up a warning saying it needs SP1 for Vista, but installing it makes no difference. No ideas about what I can possibly do to fix this?

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• Is there a efficient way to do multiple test cases in c?

  - by Ahmed Abdelaal

  I use MS Visual Studio and I am new to C++, so I am just wondering if there is an faster more efficient way to do multiple test cases instead of keep clicking CTRL+F5 and re-opening the console many times. Like for example if I have this code #include <iostream> using namespace std; void main () { int x; cout<<"Enter a number"<<endl; cin>>x; cout<<x*2<<endl; } Is there a way I could try different values of x at once and getting the results together? Thanks

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• libcurl - unable to download a file

  - by marmistrz

  I'm working on a program which will download lyrics from sites like AZLyrics. I'm using libcurl. It's my code lyricsDownloader.cpp #include "lyricsDownloader.h" #include <curl/curl.h> #include <cstring> #include <iostream> #define DEBUG 1 ///////////////////////////////////////////////////////////////////////////// size_t lyricsDownloader::write_data_to_var(char *ptr, size_t size, size_t nmemb, void *userdata) // this function is a static member function { ostringstream * stream = (ostringstream*) userdata; size_t count = size * nmemb; stream->write(ptr, count); return count; } string AZLyricsDownloader::toProviderCode() const { /*this creates an url*/ } CURLcode AZLyricsDownloader::download() { CURL * handle; CURLcode err; ostringstream buff; handle = curl_easy_init(); if (! handle) return static_cast<CURLcode>(-1); // set verbose if debug on curl_easy_setopt( handle, CURLOPT_VERBOSE, DEBUG ); curl_easy_setopt( handle, CURLOPT_URL, toProviderCode().c_str() ); // set the download url to the generated one curl_easy_setopt(handle, CURLOPT_WRITEDATA, &buff); curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, &AZLyricsDownloader::write_data_to_var); err = curl_easy_perform(handle); // The segfault should be somewhere here - after calling the function but before it ends cerr << "cleanup\n"; curl_easy_cleanup(handle); // copy the contents to text variable lyrics = buff.str(); return err; } main.cpp #include <QString> #include <QTextEdit> #include <iostream> #include "lyricsDownloader.h" int main(int argc, char *argv[]) { AZLyricsDownloader dl(argv[1], argv[2]); dl.perform(); QTextEdit qtexted(QString::fromStdString(dl.lyrics)); cout << qPrintable(qtexted.toPlainText()); return 0; } When running ./maelyrica Anthrax Madhouse I'm getting this logged from curl * About to connect() to azlyrics.com port 80 (#0) * Trying 174.142.163.250... * connected * Connected to azlyrics.com (174.142.163.250) port 80 (#0) > GET /lyrics/anthrax/madhouse.html HTTP/1.1 Host: azlyrics.com Accept: */* < HTTP/1.1 301 Moved Permanently < Server: nginx/1.0.12 < Date: Thu, 05 Jul 2012 16:59:21 GMT < Content-Type: text/html < Content-Length: 185 < Connection: keep-alive < Location: http://www.azlyrics.com/lyrics/anthrax/madhouse.html < Segmentation fault Strangely, the file is there. The same error is displayed when there's no such page (redirect to azlyrics.com mainpage) What am I doing wrong? Thanks in advance EDIT: I made the function for writing data static, but this changes nothing. Even wget seems to have problems $ wget http://www.azlyrics.com/lyrics/anthrax/madhouse.html --2012-07-06 10:36:05-- http://www.azlyrics.com/lyrics/anthrax/madhouse.html Resolving www.azlyrics.com... 174.142.163.250 Connecting to www.azlyrics.com|174.142.163.250|:80... connected. HTTP request sent, awaiting response... No data received. Retrying. Why does opening the page in a browser work and wget/curl not? EDIT2: After adding this: curl_easy_setopt(handle, CURLOPT_FOLLOWLOCATION, 1); The log is: * About to connect() to azlyrics.com port 80 (#0) * Trying 174.142.163.250... * connected * Connected to azlyrics.com (174.142.163.250) port 80 (#0) > GET /lyrics/anthrax/madhouse.html HTTP/1.1 Host: azlyrics.com Accept: */* < HTTP/1.1 301 Moved Permanently < Server: nginx/1.0.12 < Date: Fri, 06 Jul 2012 09:09:47 GMT < Content-Type: text/html < Content-Length: 185 < Connection: keep-alive < Location: http://www.azlyrics.com/lyrics/anthrax/madhouse.html < * Ignoring the response-body * Connection #0 to host azlyrics.com left intact * Issue another request to this URL: 'http://www.azlyrics.com/lyrics/anthrax/madhouse.html' * About to connect() to www.azlyrics.com port 80 (#1) * Trying 174.142.163.250... * connected * Connected to www.azlyrics.com (174.142.163.250) port 80 (#1) > GET /lyrics/anthrax/madhouse.html HTTP/1.1 Host: www.azlyrics.com Accept: */* < HTTP/1.1 200 OK < Server: nginx/1.0.12 < Date: Fri, 06 Jul 2012 09:09:47 GMT < Content-Type: text/html < Transfer-Encoding: chunked < Connection: keep-alive < Segmentation fault

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