Before going to the program first let us understand what is a Factorial of a Number?

Factorial of a Number:

                  The factorial of a Number n, denoted by n! is the product of all positive integers less than or equal to n.

The value of 0! is 1 according to the convention for an empty product.

For example,

4! = 4 * 3 * 2 * 1 = 24

Program code for Factorial of a Number in Python:

# Python program to find the factorial of a number

#Define a factorial variable
fact = 1

# To take input from the user
num = int(input("Enter a number: "))

# check if the number is negative or positive
if num < 0:
    print("Sorry, factorial does not exist for negative numbers")
else:
    for i in range(1,num + 1):
        fact = fact*i
    print("The factorial of", num, "is", fact)

Related: Factorial of a Number in C using For Loop

Working:

• First, the computer reads the number to find the factorial of the number from the user.
• Then using for loop the value of ‘i’ is multiplied by the value of ‘f’.
• The loop continues till the value of ‘n’.Finally, the factorial value of the given number is printed.

Output: