using System;

​

public class Program

{

    static private double avg(double n1, double n2, double n3, double n4)

    {

        double sum = n1 + n2 + n3 + n4;

        double div = sum / 4;

        return div;

    }

​

    public static void Main()

    {

        start:

            Console.WriteLine("This programe calculates the mean of 4 numbers.");

        Console.WriteLine("Enter the first number.");

        double num1 = double.Parse(Console.ReadLine());

        Console.WriteLine("Enter the second number.");

        double num2 = double.Parse(Console.ReadLine());

        Console.WriteLine("Enter the third number.");

        double num3 = double.Parse(Console.ReadLine());

        Console.WriteLine("Enter the fourth number.");

        double num4 = double.Parse(Console.ReadLine());

        Console.WriteLine("The average of the four numbers is : " + avg(num1, num2, num3, num4));

        goto start;

    }

}