<?php
class ObjectTracker //对象跟踪器
{
private static $nextSerial = 0;
private $id;
private $name;

function __construct($name) //构造函数
{
$this->name = $name;
$this->id = ++self::$nextSerial;
}

function __clone() //克隆
{
$this->name = "Clone of $that->name";
$this->id = ++self::$nextSerial;
}

function getId() //获取id属性的值
{
return($this->id);
}

function getName() //获取name属性的值
{
return($this->name);
}
}

$ot = new ObjectTracker("Zeev's Object");
$ot2 = $ot->__clone();

//输出: 1 Zeev's Object
print($ot->getId() . " " . $ot->getName() . "<br>");

//输出: 2 Clone of Zeev's Object
print($ot2->getId() . " " . $ot2->getName() . "<br>");
?>