README.txt

Add a method addLast() which adds an element to the end of the linked list.

assignment.java

public class Assignment {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// create list
		LinkedList list = new LinkedList();
		
		// initialize list
		for (int i = 4; i >= 1; i--) {
			list.addFirst(i);
		}
		
		// print list
		list.print();
		
		// list size
		System.out.println(list.size());
		
		// replace element
		list.set(3, 777);
	
		// print list
		list.print();
		
		// get the last entry
		System.out.println(list.getLast());
		
		// add last
		list.addLast(123);
		// add last
		// print list
		list.print();
				
		// add last
		list.addLast(123);			
		// print list
		list.print();		
	}

}

LinkedList.java

public class LinkedList 
{
	private class ListElement
	{
		private Object el1;
		private ListElement el2;
		
		public ListElement(Object el, ListElement nextElement)
		{
			el1 = el;
			el2 = nextElement;
		}

		public ListElement(Object el)
		{
			this(el,null);
		}

		public Object first()
		{
			return el1;
		}

		public ListElement rest()
		{
			return el2;
		}

		public void setFirst(Object value)
		{
			el1 = value;
		}

		public void setRest(ListElement value)
		{
			el2 = value;
		}
	}

	private ListElement head, tail;
	private int count;

	public LinkedList()
	{
		head = null;
	}

	public void addFirst(Object o)
	{
		head = new ListElement(o,head);
		count++;

		if (count == 1) {
			tail = head;
		}
	}
	
	public void addLast(Object o)
	{
		ListElement newTail = new ListElement(o);
		tail.setRest(newTail);
		tail = newTail;
	}
	
	public Object get(int n)
	{
		ListElement d = head;
		while(n>0)
		{
			d = d.rest();
			n--;
		}
		return d.first();
	}

	public Object getFirst()
	{
		return head.first();
	}

	public Object getLast()
	{
		return tail.first();
	}	
	
	public void print()
	{
		System.out.print("Complete list = ");
		ListElement d = head;
		while(d != null)
		{
			System.out.print(d.first().toString() + " ");
			d = d.rest();
		}
		System.out.println(" ");
	}
	
	public int size() {
		return count;
	}
	
	public void set(int n, Object o) {
		ListElement d = head;

		while (n > 0) {
			d = d.rest();
			n--;
		}

		d.setFirst(o);
	}

	public int indexOf(Object o) {
		int index = -1;
		int counter = 0;
		boolean found = false;
		ListElement elem = head;

		while (!found && elem != null) {
			found = elem.first().equals(o);
			if (!found) {
				counter += 1;
				elem = elem.rest();
			}
		}

		if (found) {
			index = counter;
		}

		return index;
	}

	public boolean contains(Object o) {
		return indexOf(o) > 0;
	}
}