__construct and __destruct in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the __construct method in PHP classes?

The <code>__construct</code> method is a special function called automatically when a new object of a class is created. It is used to initialize the object's properties or run setup code.

beginner

What does the __destruct method do in a PHP class?

The __destruct method is called automatically when an object is destroyed or the script ends. It is used to clean up resources like closing files or database connections.

beginner

When exactly is the __construct method called?

It is called right after an object is created with the new keyword, before any other methods are used on the object.

intermediate

Can a PHP class have multiple <code>__construct</code> methods?

No, a PHP class can only have one <code>__construct</code> method. To handle different ways of creating objects, you can use optional parameters or method overloading techniques.

beginner

Give a simple example of a PHP class using <code>__construct</code> and <code>__destruct</code>.

Example:<br><pre>class Car {
  public function __construct() {
    echo "Car created!\n";
  }
  public function __destruct() {
    echo "Car destroyed!\n";
  }
}
$myCar = new Car();</pre>

What keyword triggers the __construct method in PHP?

A create

B start

C init

D new

The new keyword creates a new object and automatically calls the __construct method.

When is the __destruct method called?

A When the object is created

B When the object is destroyed or script ends

C When a method is called

D When a property is accessed

The __destruct method runs when the object is destroyed or the script finishes.

Can a PHP class have more than one __construct method?

A No, only one constructor is allowed

B Yes, multiple constructors are allowed

C Yes, but only if they have different names

D No, constructors are not allowed

PHP allows only one __construct method per class.

What is a common use of the __destruct method?

A To initialize object properties

B To create new objects

C To clean up resources like files or connections

D To print messages when object is created

__destruct is used to clean up resources before the object is removed.

Which of these is true about __construct?

A It runs automatically after object creation

B It runs only when called explicitly

C It runs when the object is destroyed

D It runs before the class is defined

__construct runs automatically right after an object is created.

Explain in your own words what __construct and __destruct methods do in PHP classes.

Think about what happens when you get a new item and when you throw it away.

Describe a simple real-life example where you might use both __construct and __destruct in a PHP class.

Imagine borrowing a book and returning it.