c++

Random number generation

I am using below code to generate random numbers in range... int randomNumberWithinRange(int min,int max) { int snowSize = 0; do { snowSize = rand()%max; } while( snowSize < min || snowSize > max ); return snowSize; } for(int i = 0; i < 10 ; i++) NSlog("@"%d",\t", rando...

How to convert int* to int

Hi guys, Question is how do i convert a pointer to int to an actual int I dont know if this is possible or not, but can someone please advise me Regards Paul ...

starting smartcard programming

How could one get started with smartcards programming? I am asking here about all the toolkit he needs in order to get started: books, tutorials, hardware etc. I am planning in playing around with a couple of smartcards programmers and I am pretty new to this field. Edit: I am mostly interested in programmers that play nice with Unix-l...

HTTPS and C++ - Not an easy match?

I need to access a HTTPS protected website (HTML or XML) from an C++ MFC application and I would like an easy solution. But I did a little research and it's seems to me HTTPS and C++ don't play nice and easy together. Is there any recommended class library for HTTPS web access? Should be easy to use and not too expensive. ...

[C++] How should I compare pairs of pointers (for sort predicate)

I have a STL container full of billions of the following objects pair<SomeClass*, SomeClass*> I need some function of the following form /*returns items sorted biggest first */ bool sortPredicate (pair<SomeClass*, SomeClass*>two, pair<SomeClass*, SomeClass*> one) { return ???; } Is there some trick I can use to very quickly com...

std::list iterator: get next element

I'm trying to build a string using data elements stored in a std::list, where I want commas placed only between the elements (ie, if elements are {A,B,C,D} in list, result string should be "A,B,C,D". This code does not work: typedef std::list< shared_ptr<EventDataItem> > DataItemList; // ... std::string Compose(DataItemList& dilList) {...

Best environment to port C/C++ code from Linux to Windows.

I'd like to make a big project of mine buildable on Windows platforms. The project itself it's written in C/C++ following POSIX standards, with some library dependencies such as libxml2, libcurl and so on. I'm more a Linux developer rather than a Windows developer, so i have no idea of which compiler suite i should use to port the code. ...

Using pthread condition variable with rwlock

Hello, I'm looking for a way to use pthread rwlock structure with conditions routines in C++. I have two questions: First: How is it possible and if we can't, why ? Second: Why current POSIX pthread have not implemented this behaviour ? To understand my purpose, I explain what will be my use: I've a producer-consumer model dealing ...

two threads going to do func()

2 threads going to use the same func(). The 2 threads should be mutually exclusive. How do I get it to work properly? (output should be "abcdeabcde") char arr[] = "ABCDE"; int len = 5; void func(){ for(int i = 0; i <len;i++) printf("%c,arr[i]); } ...

Why does this hex value get output as a negative number?

char buffer_b[5] = { 0xDA, 0x00, 0x04, 0x00, 0x07 }; printf("%d\n%d\n%d", buffer_b[0], buffer_b[2], buffer_b[4]); This gives me output: -38 4 7 However I am expecting: 218 4 7 Thanks. ...

Write a MAT file without using matlab headers and libraries.

Hello all, I have some data that I would like to save to a MAT file (version 4 or 5, or any version, for that matter). The catch: I wanted to do this without using matlab libraries, since this code will not necessary run in a machine with matlab. My program uses Java and C++, so any existing library in those languages that achieves this...

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

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 <i...

How to get the next prefix in C++?

Given a sequence (for example a string "Xa"), I want to get the next prefix in order lexicographic (i.e "Xb"). The next of "aZ" should be "b" A motivating use case where this function is useful is described here. As I don't want to reinvent the wheel, I'm wondering if there is any function in C++ STL or boost that can help to define th...

Base class pointer vs inherited class pointer?

Suppose I have a class Dog that inherits from a class Animal. What is the difference between these two lines of code? Animal *a = new Dog(); Dog *d = new Dog(); In one, the pointer is for the base class, and in the other, the pointer is for the derived class. But when would this distinction become important? For polymorphism, ...

string Comparison

I want to compare two user input strings, but not able to do so... #include "stdafx.h" #include "iostream" #include "string" using namespace std; int _tmain(int argc, _TCHAR* argv0[]) { string my_string; string my_string2; cout<<"Enter string"<<endl; cin>>my_string; cout<<"Enter 2nd string"<<endl; cin>>my_string...

How to correctly inherit std::iterator.

Guys if I have class like below: template<class T> class X { T** myData_; public: class iterator : public iterator<random_access_iterator_tag,/*WHAT SHALL I PUT HERE? T OR T** AND WHY?*/> { T** itData_;//HERE I'M HAVING THE SAME TYPE AS MAIN CLASS ON WHICH ITERATOR WILL OPERATE }; }; Questions are in code next to appropriate lines. Th...

avoiding the tedium of optional parameters

If I have a constructor with say 2 required parameters and 4 optional parameters, how can I avoid writing 16 constructors or even the 10 or so constructors I'd have to write if I used default parameters (which I don't like because it's poor self-documentation)? Are there any idioms or methods using templates I can use to make it less te...

c++ property class structure

I have a c++ project being developed in QT. The problem I'm running in to is I am wanting to have a single base class that all my property classes inherit from so that I can store them all together. Right now I have: class AbstractProperty { public: AbstractProperty(QString propertyName); virtual ...

A reference that is not to 'const' cannot be bound to a non-lvalue

Hello, Am struggling a bit with this. Am declaring: BYTE *pImage = NULL; Used in call: m_pMyInterface->GetImage(i, &imageSize, &pImage); Visual C++ 2003 compiler error: error C2664: 'CJrvdInterface::GetImage' : cannot convert parameter 3 from 'BYTE **__w64 ' to 'BYTE **& ' A reference that is not to 'const' cannot be boun...

why optimization does not happen?

hi. I have C/C++ code, that looks like this: static int function(double *I) { int n = 0; // more instructions, loops, for (int i; ...; ++i) n += fabs(I[i] > tolerance); return n; } function(I); // return value is not used. compiler inlines function, however it does not optimize out n manipulations. I would ex...