In mathematics, a factorial of a number is calculated by multiplying that number by all of the successive values less than it, stopping at 1. For example, factorial of 4 is written 4! and calculated...

1. In mathematics, a factorial of a number is calculated by multiplying that number by all of the successive values less than it, stopping at 1. For example, factorial of 4 is written 4! and calculated as:

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

Write a program consisting of two functions (plus the main function). The first function should read in a number and then return this value back to the main function. This value should then be passed as a parameter (by value) into the second function which calculates and displays the factorial. Note: validate the input value (in the first function) to be greater than 1.