__clone for object copying in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to clone the object.

PHP

<?php
class Person {
    public $name;
}

$original = new Person();
$original->name = "Alice";
$copy = [1] $original;
echo $copy->name;
?>

Drag options to blanks, or click blank then click option'

Aclone

Bcopy

Cnew

Dduplicate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'new' instead of 'clone' to copy an object.

Using 'copy' which is not a PHP keyword.

In PHP, the 'clone' keyword is used to create a copy of an object.

2fill in blank

medium

Complete the __clone method to reset the id property when cloning.

PHP

<?php
class User {
    public $id;
    public $name;

    public function __clone() {
        $this->[1] = null;
    }
}

$user1 = new User();
$user1->id = 1;
$user1->name = "Bob";
$user2 = clone $user1;
echo $user2->id;
?>

Drag options to blanks, or click blank then click option'

Aid

Bname

Cclone

Dcopy

Attempts:

3 left

💡 Hint

Common Mistakes

Resetting the wrong property like 'name'.

Trying to call 'clone' or 'copy' inside __clone method.

Inside __clone, you can reset properties like 'id' to null to indicate a new object.

3fill in blank

hard

Fix the error in cloning an object with a nested object property.

PHP

<?php
class Address {
    public $city;
}

class Employee {
    public $name;
    public $address;

    public function __clone() {
        $this->address = [1] $this->address;
    }
}

$addr = new Address();
$addr->city = "Paris";
$emp1 = new Employee();
$emp1->name = "Eve";
$emp1->address = $addr;
$emp2 = clone $emp1;
$emp2->address->city = "London";
echo $emp1->address->city;
?>

Drag options to blanks, or click blank then click option'

Acopy

Bnew

Cclone

Dduplicate

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the nested object directly without cloning.

Using 'new' without parameters.

To clone nested objects, you must clone them explicitly inside __clone.

4fill in blank

hard

Fill both blanks to create a deep clone of an object with nested objects.

PHP

<?php
class Engine {
    public $power;
}

class Car {
    public $model;
    public $engine;

    public function __clone() {
        $this->[1] = [2] $this->engine;
    }
}

$engine1 = new Engine();
$engine1->power = 200;
$car1 = new Car();
$car1->model = "Sedan";
$car1->engine = $engine1;
$car2 = clone $car1;
$car2->engine->power = 250;
echo $car1->engine->power;
?>

Drag options to blanks, or click blank then click option'

Aengine

Bmodel

Cclone

Dnew

Attempts:

3 left

💡 Hint

Common Mistakes

Cloning the wrong property like 'model'.

Using 'new' instead of 'clone' for the nested object.

Inside __clone, clone the nested 'engine' object to avoid shared references.

5fill in blank

hard

Fill all three blanks to clone an object and reset its id and timestamp properties.

PHP

<?php
class Document {
    public $id;
    public $content;
    public $timestamp;

    public function __clone() {
        $this->[1] = null;
        $this->[2] = time();
        $this->[3] = strtoupper($this->content);
    }
}

$doc1 = new Document();
$doc1->id = 123;
$doc1->content = "hello";
$doc1->timestamp = 1650000000;
$doc2 = clone $doc1;
echo $doc2->id . ' ' . $doc2->timestamp . ' ' . $doc2->content;
?>

Drag options to blanks, or click blank then click option'

Aid

Btimestamp

Ccontent

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Resetting wrong properties or missing to update timestamp.

Using undefined properties like 'name'.

Reset 'id' to null, update 'timestamp' to current time, and modify 'content' to uppercase in __clone.