How to declare and check Null Value in Integer datatype in C#

using System.IO;
using System;
class NullableType
{
    static void Main(string[] args)
    {
        int ? myInt1 = 15;
        int ? myInt2 = null;
        if (myInt1 != null)
        {
            Console.WriteLine("Value of Nullable Type via != Comparision: {0}", myInt1);
        }
        if (myInt2.HasValue)
        {
            Console.WriteLine("Value of Nullable Type via HasValue Property: {0}", myInt2);
        } else
        {
            Console.WriteLine("It contains Null Value");
        }
    }
}