package chap1;

import java.util.Iterator;

public class LinkedStack<Item> implements Iterable<Item>

{

private Node<Item> top;

private int N = 0;

public boolean isEmpty()

{

return (N == 0);

}

public int size()

{

return N;

}

public void push(Item item)

{

Node<Item> oldFirst = this.top;

top = new Node<Item>();

top.item = item;

top.next = oldFirst;

N++;

}

public Item pop()

{

Item item = top.item;

top = top.next;

N--;

return item;

}

public Item peek()

{

return top.item;

}

@Override

public Iterator<Item> iterator()

{

return new LinkedListIterator<Item>(top);

}

@Override

public String toString()

{

Node<Item> temp = top;

String result = null;

for(; temp != null; temp = temp.next)

{

if(temp == top)

result = temp.item.toString();

else

result += "->" + temp.item;

}

return result;

}

}