/////////////////////////linkedlist
/******************************
*  Week 2 lab - exercise 1:   *
*   a simple LinkedList class  *
*******************************/

/**
 * Class implementing a linked list.
 */
public class LinkedList
{

    private Node first;  //dummy header node

    /**
     * Initializes the list to empty creating a dummy header node.
     */
    public LinkedList()
    {
        first = new Node();
    }

    /**
     * Determines whether the list is empty
     *
     * @return true if the list is empty, false otherwise
     */
    public boolean isEmpty()
    {
        return (first.getNext() == null);
    }

    /**
     * Prints the list elements.
     */
    public void display()
    {
        Node current = first.getNext();

        while (current != null)
        {
            System.out.print(current.getInfo() + " ");
            current = current.getNext();
        }

        System.out.println();
    }

    /**
     * Adds the element x to the beginning of the list.
     *
     * @param x element to be added to the list
     */
    public void add(int x)
    {
        Node p = new Node();

        p.setInfo(x);
        p.setNext(first.getNext());

        first.setNext(p);
    }

    /**
     * Deletes an item from the list. Only the first occurrence of the item in
     * the list will be removed.
     *
     * @param x element to be removed.
     */
    public void remove(int x)
    {
        Node old = first.getNext(),
                p = first;

        //Finding the reference to the node before the one to be deleted
        boolean found = false;
        while (old != null && !found)
        {
            if (old.getInfo() == x)
            {
                found = true;
            } else
            {
                p = old;
                old = p.getNext();
            }
        }

        //if x is in the list, remove it.
        if (found)
        {
            p.setNext(old.getNext());
        }

    }
}


/////////////////////////////////////////////////////////////////////// node class

/******************************
*  Week 2 lab - exercise 1:   *
*   a simple LinkedList class  *
*******************************/

/**
 * Linked list node.
 */
public class Node
{

    private int info;   //element stored in this node
    private Node next;  //link to next node

    /**
     * Initializes this node setting info to 0 and next to null
     */
    public Node()
    {
        info = 0;
        next = null;
    }

    /**
     * Sets the value for this node
     *
     * @param i the desired value for this node
     */
    public void setInfo(int i)
    {
        info = i;
    }

    /**
     * Sets the link to the next node
     *
     * @param l node reference
     */
    public void setNext(Node l)
    {
        next = l;
    }

    /**
     * Returns the value in this node
     *
     * @return the value in this node
     */
    public int getInfo()
    {
        return info;
    }

    /**
     * Returns the link to the next node
     *
     * @return link to the next node
     */
    public Node getNext()
    {
        return next;
    }
}




///////////////////////////////////main

/******************************
*  Week 2 lab - exercise 1:   *
*   a simple LinkedList class  *
*******************************/

public class Main
{
	public static void main(String args[])
	{
		LinkedList intList = new LinkedList();

		System.out.print("List of numbers before list creation: ");
		for (int i =0; i < 10; i++)
		{
			int info = (int)(Math.random()*10);
			System.out.print(info + " ");

			intList.add(info);
		}

		System.out.print("\nList of numbers after list creation:  ");

		intList.display();
	}
}