The program prompts the user to enter an integer to calculate its factorial. Then, it checks if the entered number is non-negative. If it is, the program calculates the factorial of the number and ...

The factorial of a number/integer is the product of that number and all of the numbers below it. It is denoted as 5! (factorial of 5). - 0! = 1 - 1! = 1 - 2! = 2 * 1 ...