Test Average and Grade C$++$

Write a program that asks the user to enter five test scores.$$ The program should display a letter grade for each score as they are entered, and the average of all test scores at the end.$$ Design the following functions in the program:

calcAverage$--$ This function should accept five test scores as arguments and return the average of the scores.

determineGrade$--$ This function should accept a test score as an argument and return a letter grade for the score $($as a string$),$ based on the following grading scale:

A:$90-100$B:$80-89$C:$70-79$D:$60-69$F:$0-59$