新人学习PHP问题，发现书上代码不对
在书上发现一段代码，敲下来后发现不对。。
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><br />
<?php<br />
class Person<br />
{<br />
private $name;<br />
private $sex;<br />
private $age;<br />
<br />
function __construct($name="",$sex="男",$age=23)<br />
{<br />
$this->name=$name;<br />
$this->sex=$sex;<br />
$this->age=$age;<br />
}<br />
function say()<br />
{<br />
echo "我的名字 ".$this->name."，性别 ".$this->sex."，年龄 ".$this->age."<br>";<br />
}<br />
function run()<br />
{<br />
echo $this->name."正在走路<br>";<br />
}<br />
}<br />
<br />
class Student extends Person <br />
{<br />
var $school;<br />
function study()<br />
{<br />
echo $this->name."正在".$this->school."学习<br>";<br />
}<br />
}<br />
class Teacher extends Student <br />
{<br />
var $wage;<br />
function teaching()<br />
{<br />
echo $this->sex."正在".$this->school."教学，每个月工资为".$this->wage."<br>";<br />
}<br />
}<br />
$teacher1=new Teacher("张三","男",40);<br />
$teacher1->school="沈阳工学院";<br />
$teacher1->wage=3000;<br />
<br />
$teacher1->say();<br />
$teacher1->run();<br />
$teacher1->teaching();<br />
?><br />
