Box and unbox for nullable value : nullable « Data Type « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Data Type
3. nullable

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;

    class MainClass
    {
        static void Main()
        {
            int? nullable = 5;

            object boxed = nullable;
            Console.WriteLine(boxed.GetType());

            int normal = (int)boxed;
            Console.WriteLine(normal);

            nullable = (int?)boxed;
            Console.WriteLine(nullable);

            nullable = new int?();
            boxed = nullable;
            Console.WriteLine(boxed == null);

            nullable = (int?)boxed;
            Console.WriteLine(nullable.HasValue);
        }
    }