using System;

​

namespace Program

{

    public class Program

    {

        public static void Main(string[] args)

        {

            Nullable<int> i = 5;

            Console.WriteLine(i.GetType());

            OwnNullable<int> j = 6;

            Console.WriteLine(j.GetType());

        }

    }

}

​

struct OwnNullable<T>

    where T : struct

{

    private T field;

    public OwnNullable(T value)

    {

        field = value;

    }

​

    public static implicit operator OwnNullable<T>(T value)

    {

        return new OwnNullable<T>(value);

    }

}