using System;

public class Program

{

    public static void Main()

    {

        bool? nullBool = null, trueBool = true, falseBool = false;

        Console.WriteLine("Checking nullBool against null: " + (nullBool == null));

        Console.WriteLine("Checking nullBool against false: " + (nullBool == false));

        Console.WriteLine("Checking nullBool against true: " + (nullBool == true));

        Console.WriteLine("Checking trueBool against null: " + (trueBool == null));

        Console.WriteLine("Checking trueBool against false: " + (trueBool == false));

        Console.WriteLine("Checking trueBool against true: " + (trueBool == true));

        Console.WriteLine("Checking falseBool against null: " + (falseBool == null));

        Console.WriteLine("Checking falseBool against false: " + (falseBool == false));

        Console.WriteLine("Checking falseBool against true: " + (falseBool == true));

    }

}