factorial_recursive

'''
Created on May 29, 2021

@author: Admin
'''
# n! = n * n-1 * n-2 * n-3.......1
# n! = n * (n-1)!
def factorial_iterative(n):
    # """
    #     :param n: Integer
    #     :return: n * n-1 * n-2 * n-3.......1
    # """
    fac = 1
    for i in range(n):
        fac = fac * (i+1)
    return fac

# def factorial_recursive(n):
#     """
#         :param n: Integer
#         :return: n * n-1 * n-2 * n-3.......1
#     """
#     if n ==1:
#         return 1
#     else:
#         return n * factorial_recursive(n-1)
    # 5 * factorial_recursive(4)
    # 5 * 4 * factorial_recursive(3)
    # 5 * 4 * 3 * factorial_recursive(2)
    # 5 * 4 * 3 * 2 * factorial_recursive(1)
    # 5 * 4 * 3 * 2 * 1 = 120

# 0 1 1 2 3 5 8 13
# def fibonacci(n):
#     if n==1:
#         return 0
#     elif n==2:
#         return 1
#     else:
#         return fibonacci(n-1)+ fibonacci(n-2)


n = int(input("Enter then number"))
print("Factorial Using Iterative Method", factorial_iterative(n))
# print("Factorial Using Recursive Method", factorial_recursive(number))
# print(fibonacci(number))