Linked List

Linked lists are important topics in computer science. The theory behind them is something that computer science students learn in classes like data structures and algorithms. I have created a linked list for you to study. It is fairly simple, but has the necessary methods to expand to it with a BubbleSort algorithm etc.

The following picture explains the idea behind a linked list.

Basically you have a list of these things called Nodes that are linked together. Each node is a bucket of sorts that contains a piece of data. A Linked List is a group of these buckets strung together one at a time. The head bucket is linked to the 2nd bucket, the 2nd bucket is linked to the 3rd and so on until you get to the tail bucket which isn't linked to anything.

Currently I am implementing the following methods on the linked list:
-addAtHead(Object) - creates a node and adds it to the beginning of the linked list as the head Node
-addAtTail(Object) - creates a node and adds appends it to the end of the list as the tail Node
-addAtIndex(Object) - creates a node with Object as its data and adds the node at the index
-addAtIndex(Node) - adds the node at the index
-deleteAtIndex(int index) - deletes the node at the index
-switchWithNext(int index) - switches the current index with the one right after it. This is used by the bubble sorting algorithm.
-printList() - prints out the whole LinkedLIst
-find(Node) - returns index
-find(index) - returns Node
-getSize

To Do:
-Sorting by different algorithms(bubble sort, selection sort etc.)

	/*============================================================================
	Name : LinkedList.java
	Author : Eric Swanson
	Date : Sep 7, 2011
	Version :
	Description :
	Copyright (C) 2011 Eric Swanson
	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.
	You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>.
	============================================================================*/
	class LinkedList
	{
	//Class variables for the Linked List
	private static Node head;
	private static int numNodes;
	public LinkedList(Object dat)
	{
	head = new Node(dat);
	}
	public void addAtHead(Object dat)
	{
	Node temp = head;
	head = new Node(dat);
	head.next = temp;
	numNodes++;
	}
	public void addAtTail(Object dat)
	{
	Node temp = head;
	while(temp.next != null)
	{
	temp = temp.next;
	}
	temp.next = new Node(dat);
	numNodes++;
	}
	public void addAtIndex(int index, Object dat)
	{
	Node temp = head;
	Node holder;
	for(int i=0; i < index-1 && temp.next != null; i++)
	{
	temp = temp.next;
	}
	holder = temp.next;
	temp.next = new Node(dat);
	temp.next.next = holder;
	numNodes++;
	}
	public void addAtIndex(int index, Node node)
	{
	Node temp = head;
	Node holder;
	for(int i=0; i < index-1 && temp.next != null; i++)
	{
	temp = temp.next;
	}
	holder = temp.next;
	temp.next = node;
	temp.next.next = holder;
	numNodes++;
	}
	public void deleteAtIndex(int index)
	{
	Node temp = head;
	for(int i=0; i< index - 1 && temp.next != null; i++)
	{
	temp = temp.next;
	}
	temp.next = temp.next.next;
	numNodes--;
	}
	public void switchWithNext(int index)
	{
	if(index != 0)
	{
	Node bOne = find(index - 1);
	Node one = find(index);
	Node two = one.next;
	one.next = two.next;
	bOne.next = two;
	two.next = one;
	}
	else
	{
	Node one = find(index);
	Node two = one.next;
	head = two;
	one.next = two.next;
	two.next = one;
	}
	}
	public static int find(Node n)
	{
	Node t = head;
	int index = 0;
	while(t != n)
	{
	index++;
	t = t.next;
	}
	return index;
	}
	public static Node find(int index)
	{
	Node temp=head;
	for(int i=0; i<index; i++)
	{
	temp = temp.next;
	}
	return temp;
	}
	public static void printList()
	{
	Node temp = head;
	while(temp != null)
	{
	System.out.print(temp.data + ",");
	temp = temp.next;
	}
	System.out.print("\n");
	}
	public static int getSize()
	{
	return numNodes;
	}
	class Node
	{
	//Declare class variables
	private Node next;
	private Object data;
	public Node(Object dat)
	{
	data = dat;
	}
	public Object getData()
	{
	return data;
	}
	}
	}

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