Python Program to Find Factorial of Number

This program takes an input number from user and finds the factorial of that number using a recursive function. Factorial of a number is the product of an integer and all the integers below it, for example the factorial of 4 is 4*3*2*1 = 24.

Program to find factorial

In this program we have defined a function factorial(). This function takes a number as an argument and finds the factorial of it.

# This Python Program finds the factorial of a number

def factorial(num):
    """This is a recursive function that calls
   itself to find the factorial of given number"""
    if num == 1:
        return num
    else:
        return num * factorial(num - 1)


# We will find the factorial of this number
num = int(input("Enter a Number: "))

# if input number is negative then return an error message
# elif the input number is 0 then display 1 as output
# else calculate the factorial by calling the user defined function
if num < 0:
    print("Factorial cannot be found for negative numbers")
elif num == 0:
    print("Factorial of 0 is 1")
else:
    print("Factorial of", num, "is: ", factorial(num))

Output:

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