factorial/fac3.cs - An iterative Factorial function.

Lecture 9 - slide 5 : 30 Program 1

  public static BigInteger Factorial(int n){
    if (n >= 0){
      BigInteger res = 1;
      for(int i = 1; i <= n; i++)
        res = res * i;
      return res;
    }
    else throw new ArgumentException("n must be non-negative");
  }