List all possible combinations of k integers between 1…n (n choose k)

Question

Out of no particular reason I decided to look for an algorithm that produces all possible choices of k integers between 1...n, where the order amongst the k integer doesn\'t mat

Answer 1

Here's a relatively simple/efficient nCr program I wrote a while ago in C:

main(n,k){float t=0,r=1;for(scanf("%d, %d",&n,&k);t++

Okay ... readable version. =] (Not sure if this is 1:1 corresponding with the above.)

void nCr(int n, int k) {
    float curK = 0, r = 1;
    while(curK < k) {
        ++curK;
        printf("%.0f\n", r);
        r *= (1 + n - curK) / curK;
    }
}

Instead of printing, you could yield or whatever (I don't know C#) into your list.