Write out all subsets of a given set.

all_subsets.c

#include <stdio.h>
#include <string.h>

int main()
{
    int a[] = {1, 2, 3};  
    int n = sizeof(a) / sizeof (a[0]);
    int i, j;
    for (i=0; i<(1<<n); i++) {
        for (j=0; j<n; j++)
            if (i >> j & 1)
                printf("%d ", a[j]);
        printf("\n");
    }
}

In response to http://qr.ae/Nc3yj