PHP5ÃæÏò¶ÔÏó£ºObject Cloning

PHP4:
<?
$sample1 = new StdClass();
$sample1->name = "Hasin";
$sample2 = $sample1;
$sample2->name = "Afif";
echo $sample1->name;
?>
In PHP4 it works differently; it will output Hasin, as both are different from 
each other.
PHP5:
<?
$sample1 = new StdClass();
$sample1->name = "Hasin";
$sample2 = $sample1;
$sample2->name = "Afif";
echo $sample1->name;
?>
The output is Afif
PHP5:
<?
$sample1 = new stdClass();
$sample1->name = "Hasin";
$sample2 =clone $sample1;
$sample2->name = "Afif";
echo $sample1->name;
?>
The output now would be Hasin.
__clone·½·¨µÄʹÓÃ
ĬÈϵØ,ÓÃ__clone·½·¨½«½¨Á¢Ò»¸öÓëÔ­¶ÔÏóÓµÓÐÏàͬÊôÐԺͷ½·¨µÄ¶ÔÏó. Èç¹ûÄãÏëÔÚ¿Ë¡ʱ¸Ä±äĬÈϵÄÄÚÈÝ,ÄãÒªÔÚ__cloneÖи²Ð´(ÊôÐÔ»ò·½·¨).
¿Ë¡µÄ·½·¨¿ÉÒÔûÓвÎÊý,µ«Ëüͬʱ°üº¬thisºÍthatÖ¸Õë(thatÖ¸Ïò±»¸´ÖƵĶÔÏó). Èç¹ûÄãÑ¡Ôñ¿Ë¡×Ô¼º,ÄãҪСÐĸ´ÖÆÈκÎÄãÒªÄãµÄ¶ÔÏó°üº¬µÄÐÅÏ¢,´Óthatµ½this. Èç¹ûÄãÓÃ__cloneÀ´¸´ÖÆ. PHP²»»áÖ´ÐÐÈκÎÒþÐԵĸ´ÖÆ,
ÏÂÃæÏÔʾÁËÒ»¸öÓÃϵÁÐÐòÊýÀ´×Ô¶¯»¯¶ÔÏóµÄÀý×Ó:
class ObjectTracker //¶ÔÏó¸ú×ÙÆ÷
{
private static $nextSerial = 0;
private $id;
private $name;
function __construct($name) //¹¹Ô캯Êý
{
$this->name = $name;
$this->id = ++self::$nextSerial;
}
function __clone() //¿Ë¡
{
$this->name = "Clone of $this->name";
$this->id = ++self::$nextSerial;
}
function getId() //»ñÈ¡idÊôÐÔµÄÖµ
{
return($this->id);
}
function getName() //»ñÈ¡nameÊôÐÔµÄÖµ
{
return($this->name);
}
}
$ot = new ObjectTracker("Zeev's Object");
$ot2 = clone$ot;
//Êä³ö: 1 Zeev's Object
print($ot->getId() . " " . $ot->getName() . "
");
//Êä³ö: 2 Clone of Zeev's Object
print($ot2->getId() . " " . $ot2->getName() . "
");
?>