using System;

public class Program

{

    class FortyTwo

    {

        public int? Foo { get; set; }

    }

    public static void Main()

    {

        var a = new FortyTwo { Foo = 1 };

        var b = new FortyTwo { Foo = 1 };

        Console.WriteLine("Test 1: " + (a.Foo == b.Foo).ToString());

        a.Foo = 1; b.Foo = 2;

        Console.WriteLine("Test 2: " + (a.Foo == b.Foo).ToString());

        a.Foo = 1; b.Foo = null;

        Console.WriteLine("Test 3: " + (a.Foo == b.Foo).ToString());

        a.Foo = null; b.Foo = null;

        Console.WriteLine("Test 4: " + (a.Foo == b.Foo).ToString());

    }

}