using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main(string[] args){

        var t1 = OK();

        var t2 = NotOK();

        Console.WriteLine("t1 type is "  + t1.GetType().Name);

        Console.WriteLine("t2 type is "  + t2.GetType().Name);

        if(t2.HasValue())

        {

            List<byte> search = t2.GetValue().Where(b => b > 0).ToList();

            foreach(byte num in search){

                Console.WriteLine(num); 

            }

        }

    }

    private struct Maybe<T>

    {

        private readonly T value;

        private readonly bool hasValue;

​

        private Maybe(T value)

        {

            this.value = value;

            hasValue = true;

        }

​

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

        {

            return value == null ? new Maybe<T>() : new Maybe<T>(value);

        }

        public bool HasValue(){

            return this.hasValue;   

        }

        public T GetValue(){

            return this.value;  

        }

    }

    private static Maybe<byte> OK()

    {

        return 5;

    }

    private static Maybe<IEnumerable<byte>> NotOK()

    {

        Byte[] a = new byte[] { 1, 2 };

        Console.WriteLine(a.GetType().Name);

        return a;

    }

}