PHP与数据结构之带头结点的栈的链式存储结构

<?php
/*
* use php write stack
* 栈的链式存储(链栈，单链表尾部添加)
* 定义一个结点node
*/
class node{
//存储单元
private $data;
//指向下一个的“指针”
private $next;
//初始化node
public function __construct()
{
$this->data=null;
$this->next=null;
}

/**
* @param null $data
*/
public function setData($data)
{
$this->data = $data;
}

/**
* @return null
*/
public function getData()
{
return $this->data;
}

/**
* @return null
*/
public function getNe
4000
xt()
{
return $this->next;
}

/**
* @param null $next
*/
public function setNext($next)
{
$this->next = $next;
}
}
class linkStack
{
//node 对象
private $obj;
//count 记录总长度
private static $count;
//top 始终指向栈顶元素
private $top;
//初始化链栈
public function __construct()
{
//栈顶为空，空栈
$this->top=null;
//计数器初始化为0
self::$count=0;
//构造头结点
$this->pushLinkStack();
}
//获取node结点函数
private function setNode()
{
return new node();
}
//入栈操作
public function pushLinkStack($insert=null)
{
//添加node结点
$this->obj=$this->setNode();
//赋值数据
$this->obj->setData($insert);
//“指针”后移
$this->obj->setNext($this->top);
//重新定义“指针位置”
$this->top=$this->obj;
//var_dump($this->top);
//计数器加一
if ($insert!=null)
self::$count++;
}
//显示函数
public function out()
{
$oobj=$this->obj;
while($oobj->getNext()!=null){

echo $oobj->getData()."<br>";
$oobj=$oobj->getNext();
}
echo $this->top->getData();
}
//栈顶弹出元素
public function popLinkStack()
{
//如果栈空，则echo提示
if ($this->obj->getNext()==null){
echo "栈以空";
}else{
//如果栈未空
$this->obj=$this->obj->getNext();
$this->top=$this->obj;

}
}
}
/*$a=new linkStack();
$a->pushLinkStack(1);
$a->pushLinkStack(2);
$a->pushLinkStack(3);
$a->out();
$a->popLinkStack();
$a->out();*/