using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please enter your first test score");

​

        //variables

        double testScore = double.Parse(Console.ReadLine()); //changing the number into a string

        double average = 0;

        int counter = 1;

​

​

        while (testScore != 0)

        {

            average += testScore; 

            counter++;

​

            Console.WriteLine("Please enter your another test score");

            testScore = double.Parse(Console.ReadLine());

​

        }

​

        Console.WriteLine("The average of your test score is : {0}", average/counter); //displaying the average

​

    }

}