Interview Question - how do print out all the items in a power set for a given set

Given a set {a, b, c} how do you print out all elements of the power set

If a set has N items the power set has 2 to the power N items in it
That includes the null set

Solution

    int powerSet;
    powerSet=pow(2,N);
    for(i = 0; i<(powerSet);i++)
   {
        for(j=0;j<N;j++)
{
                 if((i & (1<<j)))
 {
                  printf("%c ",y[j]);
                 }
        }
        printf("\n");
    }          
    printf("\n");

Explanation

The outer loop executes 2^N times. Each item it prints one element in the power set S.

The inner loop uses the condition i & (1<<j) to determine whether to print individual items for the element of the power set