using System;

public class Program

{

    public static void Main()

    {

        CompareOld();

        Compare();

        //Console.WriteLine("Hello World");

    }

        public static T GetData<T> () 

                    where T : class, new()

    {

    return Bool () ? null : new T ();

    }

    public static bool Bool ()

    {

    return new Random ().Next () % 2 == 0 ? true : false;

    }

    public static void CompareOld ()

    {

    var a = GetData<Object> ();

    if (a == null) {

        Console.WriteLine ("Can't compare");

        return;

    }

    var b = GetData<Object> ();

    if (b == null) {

        Console.WriteLine ("Can't compare");

        return;

    }

    if (a == b)

        Console.WriteLine ("a == b");

    else

        Console.WriteLine ("a != b");

    Console.WriteLine ("finished!");

    }

    public static void Compare ()

{

    var res = Defend (GetData<Object> (), 

                  (a) => Defend (GetData<Object> (), 

                      (b) => a == b ? "a == b" : "a != b"));

    Console.WriteLine (res);

    Console.WriteLine ("finished!");

}

    public static string Defend (object a, Func<object, string> f)

    { 

       return a == null ? "Can't compare" : f (a);

    }

    public static bool Defend (object o)

    {

        if (o == null) {

            Console.WriteLine ("Can't compare");

            return false;

        }

        return true;

    }

​

}

​

​

​

​

​