using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp18
{
    class Program
    {
        static void Main(string[] args)
        {
            ListLinked list = new ListLinked();

            list.Add(5);
            list.Add(4);
            list.Add(10);
            list.Add(550);
            list.Add(1);

            foreach (int i in list)
            {
                Console.WriteLine(i);
            }

        Console.ReadKey();
        }
    }

    class ListLinked : IEnumerable<int>
    {
        private Node _root;
        public int Count { get; private set; }

        public void Add(int value)
        {
            Node curNode = _root;

            if (curNode == null)
            {
                _root = new Node(value, null);
            }
            else
            {
                Node newNode = new Node(value, null);
                newNode.Next = curNode;
                _root = newNode;
            }
        }

        public IEnumerator<int> GetEnumerator()
        {
            Node timeNode = _root;
            while (timeNode != null)
            {
                yield return timeNode.Data;
                timeNode = timeNode.Next;
            }
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            throw new NotImplementedException();
        }
    }

    class Node
    {
        public Node Next;
        public int Data;

        public Node(int data, Node next)
        {
            Next = next;
            Data = data;
        }
    }
}