Write a C++ program that asks for a student's grades on three exams. Your program should have the following functions: - getScore: Asks the user to enter one test score. If the score is invalid (less than 0 or greater than 100), ask the user to re-enter the score. Once a valid score is entered, return it. - calculateAverage: Takes three test scores as arguments. It calculates the average of three scores and returns it. Your main function should call getScore three times, assigning the return value of each call to one of three different variables. It should then call calculateAverage, passing those three variables, and print out its return value