PHP的对象和类

<?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>"); 
?>