//This program finds combinations using the recursive method

/*****Instructions*******
To see how it works for other combinations
Try setting N_NUM to other numbers (must not be greater than 10)
Try setting R_NUM to other numbers (must not be greater than N_NUM)
*************************/

#include<iostream>

using namespace std;

//function prototype
void char_combination(char n[],int n_column,
            char r[], int r_size, int r_column, int loop);

int main()
{
        const int N_NUM=7;
        const int R_NUM=3;

        char n[]="abcdefg";

        char r[R_NUM+1];//+1 for the NULL character
        r[R_NUM]='\0';

        char_combination(n,0,r,R_NUM,0,N_NUM-R_NUM);

        cout<<"Complete!"<<endl;
        return 0;
}

void char_combination(char n[],int n_column,
            char r[], int r_size, int r_column, int loop)
{
        int localloop=loop;
        int local_n_column=n_column;

        ///////Display the string code/////////
        if(r_column>(r_size-1))
        {
                cout<<r<<endl;
                return;
        }
        /////End of displaying string code//////

        for(int i=0;i<=loop;++i)
        {
                r[r_column]=n[n_column+i];
                ++local_n_column;
                char_combination(n,local_n_column,r,r_size,r_column+1,localloop);
                --localloop;
        }
}