# Python Find the factorial of a number using recursion

Factorial in Python: Here, we will figure out how to locate the factorial of a given number utilizing the recursion in Python?

Given a whole number and we need to locate the factorial of the number utilizing recursion in Python.

Example:

`````` Input:
num = 3

Output:
Factorial of 3 is: 6
#3! = 3x2x1 = 6``````

Note: Factorial of 0 and 1 will be 1

Program

``````# Python code to find factorial using recursion

# recursion function definition
# it accepts a number and returns its factorial
def factorial(num):
# if number is negative - print error
if num < 0:
print("Invalid number...")
# if number is 0 or 1 - the factorial is 1
elif num == 0 or num == 1:
return 1
else:
# calling function itself i.e. recursive
return num * factorial(num - 1)

# main code
if __name__ == '__main__':
#input the number
x = int(input("Enter an integer number: "))
print("Factorial of ", x, " is = ", factorial(x))

x = int(input("Enter another integer number: "))
print("Factorial of ", x, " is = ", factorial(x))

x = int(input("Enter another integer number: "))
print("Factorial of ", x, " is = ", factorial(x))``````

Output

``````Enter an integer number: 5
Factorial of  5  is =  120
Enter another integer number: 0
Factorial of  0  is =  1
Enter another integer number: -3
Invalid number...
Factorial of  -3  is =  None``````
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