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<int> list = new ListLinked<int>();

            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();
        }
    }


    public class ListLinked<T> : IEnumerable<T>
    {
        private Node<T> _root;
        private Node<T> lastNode;

        public ListLinked()
        {
            _root = new Node<T>(default(T));
            lastNode = _root;
        }

        public void Add(T data)
        {
            lastNode.Next = new Node<T>(data);
            lastNode = lastNode.Next;
        }

        public IEnumerator<T> GetEnumerator()
        {
            return new LLEnumerator<T>(_root);
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }
    }


    public class LLEnumerator<T> : IEnumerator<T>
    {
        private Node<T> currenNode;

        public LLEnumerator(Node<T> current)
        {
            this.currenNode = current;
        }

        public T Current => currenNode.Data;

        object IEnumerator.Current => Current;

        public bool MoveNext()
        {
            if (currenNode == null)
            {
                return false;
            }
            currenNode = currenNode.Next;
            return (currenNode != null);
        }

        public void Dispose()
        {

        }

        public void Reset()
        {
            throw new NotImplementedException();
        }
    }
    public class Node<T>
    {
        public T Data { get; }
        public Node<T> Next { get; set; }
        public Node(T data)
        {
            Data = data;
        }
    }

}