Function factorial

other/primelib.py:567–581

input: positive integer 'n' returns the factorial of 'n' (n!)

(n)

# -----------------------------------------------------------------
    
def factorial(n):
    """
        input: positive integer 'n'
        returns the factorial of 'n' (n!)
    """
    
    # precondition
    assert isinstance(n,int) and (n >= 0), "'n' must been a int and >= 0"
    
    ans = 1 # this will be return.
    
    for factor in range(1,n+1):
        ans *= factor
    
    return ans
    
# -------------------------------------------------------------------