import java.util.ArrayList;

public class LinkedList<E>
{
    private ListNode head;

    public LinkedList( )
    {
        head = null;
    }

    public void showList( )
    {
        ListNode position = head;
        while (position != null)
        {
            System.out.println(position.data);
            position = position.link;
        }
    }

    public int length( )
    {
        int count = 0;
        ListNode position = head;
        while (position != null)
        {
            count++;
            position = position.link;
        }
        return count;
    }

    public void addANodeToStart(E addData)
    {
        head = new ListNode(addData, head);
    }

    public void deleteHeadNode( )
    {
        if (head != null)
            head = head.link;
        else
        {
            System.out.println("Deleting from an empty list.");
            System.exit(0);
        }
    }

    public boolean onList(E target)
    {
        return find(target) != null;
    }

    private ListNode find(E target)
    {
		boolean found = false;
        ListNode position = head;
        while ((position != null) && !found)
        {
            E dataAtPosition = position.data;
            if (dataAtPosition.equals(target))
			    found = true;
			else
				position = position.link;
        }

        return position; 
    }

    public ArrayList<E> toArrayList( )
    {
        ArrayList<E> list = new ArrayList<E>(length( ));
        ListNode position = head;
        while (position != null)
        {
            list.add(position.data);
            position = position.link;
        }

        return list;
    }

    private class ListNode
    {
        private E data;
        private ListNode link;

        public ListNode( )
        {
            link = null;
            data = null;
        }

        public ListNode(E newData, ListNode linkValue)
        {
            data = newData;
            link = linkValue;
        }
    }
}