c02p082.txt

Data Abstraction & Problem Solving with C++源码

int c(int n, int k)
// ---------------------------------------------------
// Computes the number of groups of k out of n things.
// Precondition: n and k are nonnegative integers.
// Postcondition: Returns c(n, k).
// ---------------------------------------------------
{
   if ( (k == 0) || (k == n) )
      return 1;
   else if (k > n)
      return 0;
   else
      return c(n-1, k-1) + c(n-1, k);
}  // end c