php类和对象

class Cart
{
var $items; // 购物车中的项目
// 把 $num 个 $artnr 放入车中
function add_item ($artnr, $num)
{
$this->items[$artnr] += $num;
}
// 把 $num 个 $artnr 从车中取出
function remove_item ($artnr, $num)
{
if ($this->items[$artnr] > $num) {
$this->items[$artnr] -= $num;
return true;
} else {
return false;
}
}
}
?>

$obj111cn_.net = new Cart;

class Session
{
public function __construct()
{
echo '构造函数执行';
}
public function __destruct()
{
echo '析构函数执行';
}
}
$Obj = new Session;
unset($Obj);//删除对象， __destruct()会被调用的
//输出
//构造函数执行
/析构函数执行
?>

class Session
{
public $age = 20;
public $sub = 'www.111cn.net';
public function __clone()
{
$this->sub=clone $this->sub;
}
}
class Session 2
{
public $value=5;
}
$s = new Session;
$s->sub=new Session 2;
$s2 = clone $s;
$s->sub->$value =10;
echo $s2->sub->$value;
?>

class Session
{
public $age = 20;
public $sub = '111cn.net';
public function __clone()
{
$this->sub=clone $this->sub;
}
}
class Session 2
{
public $value=5;
}
$s = new Session;
$s->sub=new Session 2;
$s2 = clone $s;
$s->sub->$value =10;
echo $s2->sub->$value;
?>