An iterative Factorial function with a precondition - not C# 3.0. | Lecture 9 - slide 5 : 30 Program 2 |
public static BigInteger Factorial(int n){ require n >= 0; BigInteger res = 1; for(int i = 1; i <= n; i++) res = res * i; return res; ensure res = n * n-1 * ... * 1; } | A precondition: It is required that n is non-negative. Must be checked by the caller. |