设计泛型堆栈类

package com.type.ch02;

public class LinkedStack<T> {

	private static class Node<U>{
		U item;
		Node<U> next;
		Node() {
			this.item = null;
			this.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;
	}
	
	public static void main(String[] args) {
		LinkedStack<String> lss = new LinkedStack<String>();
		for(String s : "aaa bbb ccc".split(" ")){
			lss.push(s);
		}
		String s;
		while((s=lss.pop()) != null){
			System.out.println(s);
		}
	}
}

 

ccc
bbb
aaa