#Jonathan Hudson
#Student Number 12347890
#Date: 2020-08-26
#Lecture Practice

# Compute n-factorial using recursion

# Compute n-factor
# Parameters:
#   n: The number for which the factorial is computed
# Returns: n-factorial
def factorial(n):
  # Display a message each time that the factorial function is called so that
  # we can see the recursive calls as they occur
  print("Computing", n, "factorial...")

  # Base case: 0! = 1
  if n == 0:
    return 1
  # Recursive case: n! = n * (n-1)!
  if n > 0:
    return n * factorial(n - 1)

# Read an integer, a, from the user and display a-factorial
a = int(input("Enter a non-negative integer: "))
print(a, "factorial is", factorial(a))