C++ problem, ask for help

Write a program that asks the user to enter a character c1 and three float numbers x1, x2,

x3. The program should calculate and print the result depending upon the value of c1 as

follows:

If c1 = X: the result is the maximum of x1, x2, and x3

If c1 = N: the result is the minimum of x1, x2, and x3

If c1 = V: the result is the average of x1, x2, and x3

If c1 = S : stop

The program should keep asking the user to enter and process the data until the user

enters a character S for c1.