using System;

public class Program

{

    public static void Main()

    {

        // Notice there is no implicitly defined instance of MyStaticClass!

        Console.WriteLine("The result of MyStaticClass: {0}", MyStaticClass.Sum(2,2));

        // --- Uncomment the line below and inspect the error

        // --- You cannot create an instance of a static class

        //MyStaticClass myClass = new MyStaticClass();

    }

}

​

​

// MyStaticClass - declared with the 'static' keyword

public static class MyStaticClass

{

    // --- Uncomment the line below and inspect the error

    // --- static classes cannot have constructors

    //public MyStaticClass()

    //{

    //}

    // the method Sum must be static because the class is static

    public static int Sum(int x, int y)

    {

        return x + y;

    }

}