PHPでのオブジェクトのコピーとクローン作成

class Member
{
    //声明三个私有属性
    private $name;  //会员名
    private $email; //会员邮箱
    private $score; //会员积分
    
    //构造方法
    public function __construct($name='',$email='',$score=0)
    {
        $this->name = $name;
        $this->email = $email;
        $this->score = $score;
    }
    
    //查询器(暂时省略访问控制)
    public function __get($name)
    {
        return $this->$name;
    }
    
    //设置器(暂时省略访问控制)
    public function __set($name,$value)
    {
        $this->$name = $value;
    }
    
    //克隆魔术方法在对象克隆时自动调用,针对新对象进行初始化操作
    public function __clone()
    {
        $this->score = 0;
    }
    
}

$member = new Member('peter','peter@php.cn',1000);

$member1 = $member;

$member1->score = 2000;

echo $member1->score;
echo &#39;<hr>&#39;;

var_dump($member1);  //对象id=1
var_dump($member);   //对象id=1

$member2 = clone $member;

echo $member2->score; //目前是原始值2000

$member2->score = 5000;
echo &#39;<hr>&#39;;

echo $member2->score; //新值5000
echo &#39;<hr>&#39;;

echo $member->score; //发现原对象的score属性值仍为2000,未发生变化

var_dump($member); //变量id是1
var_dump($member2); //变量id是2

$member3 = clone $member;

echo &#39;<hr>&#39;;
echo $member3->score; //0,说明克隆魔术方法已经生效