PHP 类的静态变量索引

直接上代码

<?phpclass example{    public static $pa;    public $pb;    public function __construct(){        $this->pb = ++self::$pa;    }}$a = new example;$b = new example;echo $a->pb;echo '<hr/>';echo $b->pb;?>

本来想结果应该是

1-----------------------------------------------------1

可是我错了，正确的结果是

1----------------------------------------------------------------------------------2

基础没学好，赶快补补