Write a program that performs the following tasks: 1- Define a function called Calc that: a. Accept an in value n then calculate the series: 2 3 4 n S = + + + .+ 1 2 3 n - 1 b. Then the function should return the result s. 2- Define a main function that perform the following: a. Define an integer values n, and a real value r. b. Enter the values of n. c. Call function Calc and pass a to calculate r. d. Display r