int Factorial(int N)
// ------------------------------------------------------
// Computes the factorial of an integer.
// Precondition: N >= 0.
// Postcondition: Returns N * (N-1)*...*1, if N > 0; 
// returns 1 if N = 0.
// ------------------------------------------------------
{
   int F = 1;

   for (int Integer = N; Integer > 1; --Integer)
      F *= Integer;

   return F;
}  // end Factorial