Print all Combination by Backtracking

#include<bits/stdc++.h>

using namespace std;

int n, r;

int number[10000];

void combination(int pos, int left)

{

    if(left > n-pos+1)

        return;

    if(pos == n+1)

    {

        for(int i=1; i<=r; i++)

            cout << number[i] << " ";

        cout << "\n";

        return;

    }

    if(left > 0)

    {

        number[r-left+1] = pos;

        combination(pos+1, left-1);

    }

    combination(pos+1, left);

}

int main()

{

    cout << "Enter n and r :: ";

    cin >> n >> r;

    cout << "Combination are :: \n";

    combination(1, r);

    return 0;

}