Finding the Average

Write a program to find the average of $10$ numbers that are entered by the user

Then modify the program to find the average of as many numbers as the user wants. In other words, ask the user to enter how many numbers he would like

to find the average for, then prompt him for that many values.

Modify the program again to prompt the user after finding the average to see if he would like to find the average of another set of numbers. If e

he would like to find the average of another set of numbers. If so$,$ the progran should start over by prompting him to enter the number of values he would

Change the program so that it does not prompt the user to

Change the program so that it does not prompt the user to enter how many numbers he wants to find the average for, but tells him to enter values until he

enters $-1.$ When you read a $-1$ of the values up to that point.