factorials

def factorial_recursive(n):
    """
    Computes the factorial of a non-negative number n (using recursion)
    """
    if n == 0:
        return 1
    return n * factorial_recursive(n - 1)

def factorial_iterative(n):
    """
    Computes the factorial of a non-negative number n (using iteration)
    """
    result = 1
    if n == 0:
        return 1
    for num in range(1, n + 1):
        result *= num
    return result


factorial_recursive(15)
factorial_iterative(20)