java数据结构之堆栈

建立节点类(Node.java)
package com.yz.mystack;
public class Node {
Object data;
Node next;
public Node(Object data){
this.data=data;
next=null;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public Node getNext() {
return next;
}
public void setNext(Node next) {
this.next = next;
}

}

建立链表(Link.java)
package com.yz.mystack;
public class Link {
Node head;
public Link(){
head=new Node(null);
}
public void addNode(Node node){
Node p=head;
node.setNext(p.getNext());
p.setNext(node);

}
public void delNode(){
if(!isEmploy()){
head.setNext(head.getNext().getNext());
}
}

public Node gettop(){
return head.getNext();
}
public Boolean isEmploy(){
return head.getNext()==null;
}
public void display(){
Node p=head;
while(true){
p=p.getNext();
if(p!=null){
System.out.println(p.getData());
}else{
break;
}
}
}

}

建立堆栈
 package com.yz.mystack;
public class Stack {
Link link;

public Stack(){
link=new Link();
}
public void push(Object data){
link.addNode(new Node(data));
}

public Object peek(){
return link.gettop().getData();
}
public Object pop(){
Object data=peek();
link.delNode();
return data;
}
}
测试(Man.java)
package com.yz.mystack;
public class Man {
public static void main(String[] args){
Stack stack=new Stack();
stack.push("aa");
stack.push("bb");
stack.push("cc");

System.out.println(stack.peek());
System.out.println(stack.peek());
System.out.println(stack.peek());

System.out.println(stack.pop());
System.out.println(stack.pop());
}
}