泛型鏈式堆疊

import java.util.*;
public class LinkedStack<T> {

	private static class Node<U>{
		U item;
		Node<U> next;
		Node(){
			item=null;
			next=null;
		}
		Node(U item,Node<U> next){
			this.item=item;
			this.next=next;
		}
		boolean end(){
			return item==null&&next==null;
		}
	}
	private Node<T> top=new Node<T>();
	public void push(T item){
		top=new Node<T>(item,top);
	}
	public T pop(){
		T result=top.item;
		if(!top.end())
			top=top.next;
		return result;
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		LinkedStack<String> s=new LinkedStack<String>();
		for(String p: "Phasers on stun!".split(" "))
			s.push(p);
		String p;
		while((p=s.pop())!=null)
			System.out.println(p);

	}

}