write the program in C++ only

Write a program that inputs student grades, calculates and prints the average and the corresponding letter grade. Create the following functions. REMEMBER TO CODE AND TEST ONE FUNCTION AT A TIME!

getScore Receives no input. Prompts the user to input a test score. Include a loop to validate that the score is between 0 and 100. Returns a validated score. Main will call this function 3 times to enter and store the 3 numbers.

calcAverage Receives 3 test scores as input, calculates and returns the average.

calcGrade Receives as input an average, determines and returns the letter grade. Use the standard grading scale: A = 90 to 100, B = 80 to less than 90 C = 70 to less than 80, D = 60 to less than 70, F = below 60

Note that the average and grade are printed in main (NOT in the function). Use a loop in main to continue to process more data.

Sample Output (Test case 1)

Enter test score: 70

Enter test score: 80

Enter test score: 110

Invalid, please re-enter: 92

Your average is 80.7

Your grade is B

Another? y

(continue processing other data listed below)

Additional test data:

Test scores of: 55, 88, 78

Test scores of: 85, 90, 98

Test scores of: 50, 62, 55

Test scores of 58, 65, 68