using System;

using static System.Console;

public class Program

{

    public static void Main()

    {       

        int? nullable1 = null;

        int? nullable2 = 10;

        if(nullable1.HasValue)

            WriteLine(nullable1);

        if(nullable2.HasValue)

        {

            WriteLine(nullable2);

            WriteLine(nullable2.Value);

        }

    }

}

​