Factorial of a number

Aim: Implement a program to find the factorial of a number provided by the user.

Algorithm:

1:Start

 2:Declare variables n,factorial and i.

3:Initialize variables factorial←1,i←1

4:Read value of n

5:Repeat the steps until i=n

     5.1: factorial←factorial*i

     5.2: i←i+1

6:Display factorial

7:Stop

Program:

# take input from the user

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

factorial = 1

# check if the number is negative, positive or zero

if num < 0:

   print("Sorry, factorial does not exist for negative numbers")

elif num == 0:

   print("The factorial of 0 is 1")

else:

   for i in range(1,num + 1):

       factorial = factorial*i

   print("The factorial of",num,"is",factorial)

Output :

Enter a number: -2

Sorry, factorial does not exist for negative numbers