The Subset Problem and it's recursive implementation

Suppose we have a set S with n number of elements. How many different ways can you select k  elements from the set S. So we solve the problem using recursion. Here is a video explaining the problem and below that is the recursive implementation of the subset problem.

Implementation:

int C(int n,int k) {

   if (k==0 || k==n)

     return 1;

   return C(n-1,k-1) + C(n-1,k);

}