php 深复制

<code>php</code><code>class test{
    public $num = 100;
}
$a = new test();
$b = clone $a;
$a->num = 200;
echo $b->num;//100

class test{
    public $num = 100;
}
$a = new test();
$b = $a;
$a->num = 200;
echo $b->num;//200
//数组
$a = [1,2,3];
$b = $a;
$a[1] = 5;
var_dump($b);//[1,2,3]

$a = [1,2,3];
$b = &$a;
$a[1] = 5;
var_dump($b);//[1,5,3]
//以上就是php的深复制，浅复制，对吗？
</code>

<code>php</code><code>class test{
    public $num = 100;
}
$a = new test();
$b = clone $a;
$a->num = 200;
echo $b->num;//100

class test{
    public $num = 100;
}
$a = new test();
$b = $a;
$a->num = 200;
echo $b->num;//200
//数组
$a = [1,2,3];
$b = $a;
$a[1] = 5;
var_dump($b);//[1,2,3]

$a = [1,2,3];
$b = &$a;
$a[1] = 5;
var_dump($b);//[1,5,3]
//以上就是php的深复制，浅复制，对吗？
</code>

<code>class SubTest {
    public $num = 100;
}

class Test {
    public $child;

    function __construct($child){
        $this->child = $child;
    }
}

$a = new Test(new SubTest());
// 这里进行浅拷贝
$b = clone $a;
$b->child->num = 200;

// 以下输出均是 200
echo $a->child->num, "\n";
echo $b->child->num, "\n";

class Test2 {
    public $child;

    function __construct($child){
        $this->child = $child;
    }

    // clone 完成时，此方法会被调用，在此完成深拷贝动作
    function __clone() {
        $this->child = clone $this->child;
    }
}

$a = new Test2(new SubTest());
// 这里进行深拷贝
$b = clone $a;
$b->child->num = 200;

// 以下输出是 100, 200
echo $a->child->num, "\n";
echo $b->child->num, "\n";
</code>