用链表实现栈

栈只能在栈顶操作

package suanfa;

public class PersonStack<T> implements Stack<T>{ Stack为自定义的一个接口
	private int size;
	private Node<T> top;
	@Override
	public void clear() {
		this.top=null;
		this.size=0;
	}
	@Override
	public boolean isEmpty() {		
		return this.top==null;
	}
	@Override
	public T peek() {//返回栈顶元素
		if(this.top==null)
			return null;
		return this.top.getData();
	}
	@Override
	public T pop() {
		Node<T> out=this.top;
		if(this.top==null){
			return null;
		}
		this.top=this.top.getNext();
		this.size--;
		return out.getData();
	}
	@Override
	public void push(T elment) {
		Node<T> high=new Node<T>(elment,top);
		this.top=high;
		this.size++;
	}
	@Override
	public int size() {
		return this.size;
	}
	
	
	/**测试栈
	 * @param args
	 */
	public static void main(String[] args){
		PersonStack<Integer> testStack=new PersonStack<Integer>();
		testStack.push(3);
		testStack.push(5);
		testStack.push(2);
		testStack.push(1);
		testStack.push(6);
		System.out.println("Size:"+testStack.size);
		System.out.println("栈顶元素:"+testStack.peek());
		while(!testStack.isEmpty()){
			System.out.println(testStack.pop());
		}
		System.out.println("Size:"+testStack.size);
		System.out.println("栈顶元素:"+testStack.peek());
	}
	
}
class Node<T>{//结点 用于保存结点信息
	private T data;
	private Node<T> next;
	public Node(){
		this.data=null;
		this.next=null;
	}
	public Node(T data){
		this.data=data;
		this.next=null;
	}
	public Node(T data,Node<T> next){
		this.data=data;
		this.next=next;
	}
	public void setData(T data){
		this.data=data;
	}
	public T getData(){
		return this.data;
	}
	public void setNext(Node<T> next){
		this.next=next;
	}
	public Node<T> getNext(){
		return this.next;
	}
}

自定义的接口Stack<T>

package suanfa;

public interface Stack<T> {
	public void clear();
	public boolean isEmpty();
	public T peek();
	public T pop();
	public void push(T elment);
	public int size();
}