public class LinkedStackClass extends UnorderedLinkedList
{
	public LinkedStackClass()
	{
		super();
	}

		//copy constructor
	public LinkedStackClass(LinkedStackClass otherStack)
	{
		super(otherStack);
	}//end copy constructor

	public void initializeStack()
	{
	  	initializeList();
	}

   	public boolean isEmptyStack()
	{
		return isEmptyList();
	}

	public boolean isFullStack()
	{
		return false;
	}

	public void push(DataElement newElement)
	{
	    	insertFirst(newElement);
	} //end push

	public DataElement top() throws StackUnderflowException
   	{
 		if(first == null)
       		throw new StackUnderflowException();

     	return front();
     } //end top

     public void pop()throws StackUnderflowException
     {
          if(first == null)
             throw new StackUnderflowException();

          first = first.link;

          count--;

          if(first == null)
             last = null;
     }//end pop


	public void copyStack(LinkedStackClass otherStack)
	{
		copyList(otherStack);
	}
}