Python Factorial of n is that the product of all positive descending integers. Factorial of `n`

is denoted by `n!`

.

Here, 4! is pronounced as “4 factorial”, it is also called “4 bang” or “4 shriek”.

The factorial is normally used in Combinations and Permutations (mathematics).

To understand this example, you should have knowledge of following Python programming topics:

There are many ways to write down the factorial program in Python language. let’s have a look at the two ways in which to write down the factorial program in Python.

- Factorial Program using the loop
- Factorial Program using recursion

## Source Code: **Factorial Using Loop in Python**

In this program, we are taking input from the user. Then using for loop we are calculating factorial and printing the value.

num = int(input("Enter a number: ")) fact = 1 for i in range(1,num+1): fact = fact * i print("Factorial of ",num, "is :",fact)

## Source Code: **Factorial Using Recursive Function in Python**

In this python program, we are using recursion. We have created a function called `fact_recur()`

. In that function, we are using `if else`

and in else we use a recursive function.

# Factorial using Recursion # StudyGyaan.com def fact_recur(n): if n==0: return 1 else: return(n*fact_recur(n-1)) num = 4 print("Factorial of",num,"is",fact_recur(num))

It’s also available on GitHub: https://github.com/studygyaan/python-tutorial/blob/master/python-factorial.py