using System;

public class Program

{

    public static void Main()

    {

        Object a = null;

        Object b = new Object();

        Console.WriteLine(a == b);

        Console.WriteLine(b == a);

        // null check works with roslyn compiler (C# 6), but not .net 4.5

        /*

        Console.WriteLine(b?.Equals(a));

        Console.WriteLine(a?.Equals(b));

        */

        Console.WriteLine(b.Equals(a)); 

        Console.WriteLine(a.Equals(b));

    }

}