CombinationGenerator.h

#ifndef COMBINATION_GENERATOR_H
#define COMBINATION_GENERATOR_H

#ifdef WIN32
        #pragma once
#endif

#define NULL nullptr

#include <vector>

class CombinationGenerator {
public:
    CombinationGenerator() {}
    ~CombinationGenerator();

    void                    Initialize( int n, int k );
    void                    Initialize( int n, int k, unsigned long long numCombinations );
    std::vector<int>            NextCombination();
    unsigned long long          ComputeBinomialCoefficient( int n, int k );
    unsigned long long          GetNumLeft();
    bool                    IsFinished();

private:
    int                 n;
    int                     k;
    unsigned long long          m_iNumCombinations;
    unsigned long long          m_iNumLeft;
    std::vector<int>            m_vecCurrCombination;

}; extern CombinationGenerator* g_pCombinationGen; // You'll probably only want one of these running in your project, so we'll make a global pointer to it.

#endif