Learn the use of clone in php

class Person {
    private $name;
    private $age;
    private $id;
    function __construct( $name, $age ) {
        $this->name = $name;
        $this->age = $age;
    }
    function setId( $id ) {
        $this->id = $id;
    }

    function __clone() {
        $this->id = 0;
    }
}
print "";</li>
<li>$person = new Person( "bob", 44 );</li>
<li>$person->setId( 343 );</li>
<li>$person2 = clone $person;</li>
<li>print_r( $person );</li>
<li>print_r( $person2 );</li>
<li>print "";
?>

演示代码2：

class Account {
    public $balance;
    function __construct( $balance ) {
        $this->balance = $balance;
    }
}
class Person {
    private $name;
    private $age;
    private $id;
    public $account;
    function __construct( $name, $age, Account $account ) {
        $this->name = $name;
        $this->age  = $age;
        $this->account = $account;
    }
    function setId( $id ) {
        $this->id = $id;
    }
    function __clone() {
        $this->id   = 0;
    }
}
$person = new Person( "bob", 44, new Account( 200 ) );
$person->setId( 343 );
$person2 = clone $person;
// give $person some money
$person->account->balance += 10;
// $person2 sees the credit too
print $person2->account->balance;
// output:
// 210
?>

官方文档：http://cn2.php.net/__clone