using System;

public class Program

{

    public static void Main()

    {

        LinkedList l = new LinkedList();

        l.Add("1");

        l.Add("2");

        l.Add("3");

        l.Add("4");

        l.Traverse();

        l.Reverse();

        l.Traverse();

    }

    public class LinkedList

    {

        private Node head;

        public void Add(object data)

        {

            if(head == null)

            {

                head = new Node();

                head.Data = data;

                head.Next = null;

            }

            else

            {

                Node current = head;

                while(current.Next !=null)

                {   

                    current = current.Next;

                }

                Node newNode = new Node();

                newNode.Data = data;

                newNode.Next = null;

                current.Next = newNode;

            }           

        } 

        public void Remove(Node node)

        {

        }

        public void Traverse()

        {

            if(head==null){

                Console.WriteLine("Linked list is empty, Add some nodes");

                return;

            }

            Node current = head;

            Console.WriteLine(current.Data);

            while(current.Next !=null)

            {       

                current = current.Next;

                Console.WriteLine(current.Data);

            }

        }

        public void Reverse()

        {

            Node current = head;

            Node prev = null;

            while(current!=null)

            {

                Node next = current.Next;

                current.Next = prev;

                prev = current;

                current = next;

            }

            head = prev;

        }

    }

    public class Node{

        public Node Next;

        public object Data;

    }

}