Problem Statement

Write a program that performs Credit Card Number Check. Your program should

repeatedly ask the user to input an $8-$digit number to check if it is valid, until the user

enters $-1$ to quit. $($Please note that for simplicity, now you can assume the user will

always enter $8-$digit numbers to check except for quitting the program with $-1.$ In the

coming week, we will learn how to handle the user input validation$).$ Please note that this

Lab assignment is from the Programming Project $4\mathrm{.}22\mathrm{.}21$ of the ZyBook.

Your program will implement the following algorithm:

The last digit of a credit card number is the check digit, which protects against

transactions errors such as an error in a single digit or switching two digits. The following

method is for numbers with $8$ digits