# Factorial program in Python using function | Example code

You can use the math module factorial function to create your own Factorial program in Python using function. To create your own factorial function you have to use for loop.

factorial of 5 is

``5!=5*4*3*2*1=120``

factorial of n is

``n!=n*(n-1)*....2*1``

Note: Factorial is not defined for negative numbers, and Factorial of zero(0) is: 1

## Example of factorial program in Python using function

Simple example code finds factorial of a user-given number.

``````def find_factorial(n):
f = 1
for i in range(1, n + 1):
f = f * i
return f

x = int(input("Enter a number: "))

result = find_factorial(x)

print("Factorial is:", result)``````

Output:

Use built-in function factorial() by importing math module

``````import math

x = 5

res = math.factorial(x)
print(res)``````

Output: 120

Do comment if you have any doubts or suggestions on this Python factorial code.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.