using System;

​

public class Dog

{

    public void Say()

    {

        Console.WriteLine("bark");

    }

}

​

public class Program

{

    public static void Main()

    {

        Dog rex = new Dog();

        rex.Say();

        Dog billy = new Dog(); // billy == null

        if (billy == null)

        {

            Console.WriteLine("billy is not instantiated");

            billy = new Dog(); // billy is now a Dog object

        }

​

        billy.Say();

    }

}