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

namespace LinkedStoryList
{
    class StoryList : IList
    {
        // Attributes
        private LinkedNode headNode;
        private LinkedNode tailNode;
        private int count;

        #region IList Members

        public void Add(string data)
        {
            // Make the new node
            LinkedNode newNode = new LinkedNode(data);

            // Check the head node
            if (headNode == null)
            {
                headNode = newNode;
                tailNode = newNode;
            }
            else
            {
                // Link to the previous node
                newNode.SetPrevious(tailNode);

                // Add a new thing to the end of the list
                tailNode.SetNext(newNode);
                tailNode = newNode;  
            }

            // Increment the count
            count++;
        }

        public void Add(string data, int index)
        {
            // Make the new node
            LinkedNode newNode = new LinkedNode(data);

            // Check for a valid index
            if (index < 0 || index > count - 1)
            {
                // Tell the user about faulty input
                Console.WriteLine("You entered a faulty spot in the list! Added to the end.");
                // Add data to the end
                Add(data);
            }

            // Create a temporary search node to get to the right spot in the list
            LinkedNode searchNode = headNode;

            // Loop through to get to the right spot
            for (int i = 0; i < index; i++)
            {
                searchNode = searchNode.GetNext();
            }
            
            // Link everything
            searchNode.SetPrevious(newNode);
            newNode.SetNext(searchNode);
            searchNode = searchNode.GetPrevious();
            newNode.SetPrevious(searchNode);
            searchNode.SetNext(newNode);
            
            // Update the count
            count++;
        }

        public string Remove(int index)
        {
            if (index < 0 || index > count)
            {
                return null;                
            }
            else if (index == 0)
            {
                String oldData = headNode.GetData();
                headNode = headNode.GetNext();
                headNode.SetPrevious(null);
                count--;
                return oldData;                
            }
            else if (index == count)
            {
                String oldData = tailNode.GetData();
                tailNode = tailNode.GetPrevious();
                tailNode.SetNext(null);
                count--;
                return oldData;                
            }
            else
            {
                LinkedNode searchNode = headNode;
                for (int i = 0; i < index; i++)
                {
                    searchNode = searchNode.GetNext();
                }
                LinkedNode previousNode = searchNode.GetPrevious();
                LinkedNode nextNode = searchNode.GetNext();
                previousNode.SetNext(nextNode);
                nextNode.SetPrevious(previousNode);
                count--;
                return searchNode.GetData();                
            }
        }

        public string GetElement(int index)
        {
            if (index < 0 || index > count)
            {
                return null;
            }
            else
            {
                LinkedNode searchNode = headNode;
                for (int i = 0; i < index; i++)
                {
                    searchNode = searchNode.GetNext();
                }
                return searchNode.GetData();
            }
        }

        public int Count
        {
            get { return count; }
        }

        public bool IsEmpty()
        {
            if(headNode.GetData() == null)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        #endregion

        
    }
}


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

namespace LinkedStoryList
{
    /// <summary>
    /// Represents one node in a Linked List
    /// </summary>
    public class LinkedNode
    {

        // Attributes
        private String data;   // The data in this linked node
        private LinkedNode next;  // The next node in the list;
        private LinkedNode previous; // The previous node in the list;

        /// <summary>
        /// Default constructor for a Linked Node
        /// </summary>
        public LinkedNode()
            : this(null, null, null)
        {
        }


        /// <summary>
        /// Creates a new Linked Node with data
        /// </summary>
        /// <param name="data">The data to hold in this node</param>
        public LinkedNode(String data)
            : this(data, null, null)
        {
        }


        /// <summary>
        /// Creates a new Linked Node with data that also
        /// knows about other nodes in the chain
        /// </summary>
        /// <param name="data">The data to store in this node</param>
        /// <param name="next">The next node in the chain</param>
        /// <param name="previous">The previous node in the chain</param>
        public LinkedNode(String data, LinkedNode next, LinkedNode previous)
        {
            this.data = data;
            this.next = next;
            this.previous = previous;
        }

        /// <summary>
        /// Gets the next node in the chain
        /// </summary>
        /// <returns>The next node in the chain</returns>
        public LinkedNode GetNext()
        {
            return next;
        }

        /// <summary>
        /// Gets the previous node in the chain
        /// </summary>
        /// <returns>The previous node in the chain</returns>
        public LinkedNode GetPrevious()
        {
            return previous;
        }

        /// <summary>
        /// Gets the data stored in this node
        /// </summary>
        /// <returns>The data stored in this node</returns>
        public String GetData()
        {
            return data;
        }

        /// <summary>
        /// Sets the link to the next node
        /// </summary>
        /// <param name="next">The new next node</param>
        public void SetNext(LinkedNode next)
        {
            this.next = next;
        }

        /// <summary>
        /// Sets the link to the previous node
        /// </summary>
        /// <param name="previous">The new previous node</param>
        public void SetPrevious(LinkedNode previous)
        {
            this.previous = previous;
        }

        /// <summary>
        /// Sets the data for this node
        /// </summary>
        /// <param name="data">The new data for this node</param>
        public void SetData(String data)
        {
            this.data = data;
        }

    }
}


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

namespace LinkedStoryList
{
    class Program
    {
        static void Main(string[] args)
        {
            StoryList test = new StoryList();
            test.Add("1");
            test.Add("3");
            test.Add("2", 1); 
            Console.WriteLine(test.GetElement(0));
            Console.WriteLine(test.GetElement(1));
            Console.WriteLine(test.GetElement(2));
        }
    }
}