/**
 * Author: 		Joanna Klukowska
 * Date:		Sept. 16, 2013
 * 
 * Implements LinkedList class for the second 
 * class example - naive implementation. 
 * This is iterative implementation of the methods.
 * The list is stored in unsorted order.
 * This version is still NOT correct although it fixes 
 * some of the errors of the first version.
 */
package csci102_linked_list;

public class LinkedList2 {
	
	final double ZERO = 0.0000000001;
	
	Node head;	//reference to the first Node in the list 
	
	/*
	 * Class constructor
	 */
	public LinkedList2()
	{
		head = null;
	}
	
	/*
	 * Inserts a node with valueToAdd at the end of the list.
	 */
	public void insertAtEnd ( double valueToAdd )
	{
		//create Node with the new value
		Node nodeToAdd = new Node();
		nodeToAdd.number = valueToAdd;
		nodeToAdd.link = null;
		
		Node current = head;
		//if the list is empty add the node at the head
		if (current == null)
		{
			head = nodeToAdd;
			return;
		}
		//otherwise look for the last element in the list
		while ( current.link != null )
		{
			current = current.link ;
		}
		current.link = nodeToAdd ;
	}
	
	/*
	 * Computes and returns the number of nodes in the list.
	 */
	public int size ()
	{
		int numOfNodes = 0;
		
		Node current = head;
		//if the list is empty return zero
		if (current == null)
		{
			return numOfNodes; 
		}
		//increment the counter for the first node and 
		//look for the last element in the list
		do 
		{
			current = current.link ;
			numOfNodes++; 
		} while ( current != null );
		
		return numOfNodes;
	}
	
	/*
	 * Tests if valueToFind is on the list and returns true or 
	 * false accordingly.
	 */
	public boolean find ( double valueToFind )
	{
		Node current = head;
		//if the list is empty return false
		if (current == null)
		{
			return false;
		}
		//otherwise look for the valueToFind in the list
		do 
		{
			if ( Math.abs( current.number - valueToFind ) < ZERO )
				return true;			
			current = current.link ;
			
		} while ( current != null );
		
		return false;
	}

	/*
	 * Produces a String object based on the entire list, one
	 * value per line (this may not be practical for long lists).
	 */
	public String toString()
	{
		String listInString = "";
		
		Node current = head;
		//if list is empty, return an empty string
		if (current == null)
			return listInString;
					
		//process the list
		do
		{
			listInString += String.format("%.5f\n", current.number );
			current = current.link ;
		} while ( current != null );
		
		return listInString;
	}

	/*
	 * Removes valueToRemove if it exists, otherwise returns false.
	 */
	public boolean remove( double valueToRemove)
	{
		//check if the value is there, if not, return false
		if (! find (valueToRemove) )
			return false;
		
		//otherwise locate the value and remove it
		Node current = head;
		//look for the valueToRemove
		while ( current.link != null )
		{
			if ( current.link.number == valueToRemove )
			{
				//bypass the Node with the valueToRemove 
				current.link = current.link.link;
				break;
			}		
			current = current.link ;	
		}
		return true;		
	}
}