**Python Program Factorial Three Versions** – This Python tutorial explains three different source codes of the Python factorial program.

Write a program that asks the user for a number and prints out the factorial of that number:

- Using factorial() function of math module
- Using for loop
- Using while loop

The Python has a math module. This math module contains a factorial() function that takes a positive integer as argument and returns the factorial of that number.

### How to use Python factorial() function

We will use factorial() function after importing math module in our Python program.

**Python Program Factorial Three Versions**

### The Source code of the Python factorial Program using factorial function

# Write a program that asks the user # to enter a number. # The program should display the factorial # of that number # Author: www.EasyCodeBook.com (c) from math import factorial num = int(input('Enter a number to find its factorial:')) fact = factorial(num) print('The Factorial of', num,'is:',fact)

The output is: Enter a number to find its factorial:4 The Factorial of 4 is: 24

### Python Factorial Program using for loop

# Write a program that asks the user # to enter a number. # The program should display the factorial # of that number using for loop. # Author: www.EasyCodeBook.com (c) num = int(input('Enter a number to find its factorial:')) fact = 1 for i in range(1,num+1): fact = fact * i print('The Factorial of', num,'is:',fact)

The output is as follows: Enter a number to find its factorial:5 The Factorial of 5 is: 120

### Python Factorial program using while loop

# Write a program that asks the user # to enter a number. # The program should display the factorial # of that number using while loop. # Author: www.EasyCodeBook.com (c) num = int(input('Enter a number to find its factorial:')) i = fact = 1 while i<=num: fact = fact * i i+=1 print('The Factorial of', num,'is:',fact)

The output of factrial program using while loop is: Enter a number to find its factorial:6 The Factorial of 6 is: 720