Then the user should be asked to enter a choice to run the program. After the choice is made by entering the number, 1, 2, .. etc., the corresponding program should run. First the program should take input of any variables required and then do the computation and show the result on the screen. Once the program is complete, the program should ask the user, whether program should continue or exit. If user selects continue, then the main list of programs should appear as it was displayed in the first instance.

Write a Java class called Factorial. This class defines a method called factorial() which takes as its only parameter an int called n, and returns an int representing the factorial of n. The factorial of an integer n, denoted n!, is defined as n (n 1) (n 2) . . . 1 (but note that 0! is 1). You MAY assume that n is a non-negative integer.