c$++$ Part $3$: Write a program that will read in grades, the number of which is also input by the user. The program will find the sum of those grades and pass it$,$ along with the number of grades, to a function which has a "pass by reference" parameter that will contain the numeric average of those grades as processed by the function. The main function will then determine the letter grade of that average based on a $10$point scale. $90-100$ A $80-89$ B $70-79$ C$0-59$ F Sample Run: Enter the number of grades $3$ Enter a numeric grade between $0-10090$ Enter a numeric grade between $0-10080$ Enter a numeric grade between $0-10050$ The grade is C