Parent keyword behavior in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the parent keyword do in PHP?

The <code>parent</code> keyword is used to access methods or properties from a parent class inside a child class.

beginner

How do you call a parent class constructor using <code>parent</code>?

Inside the child class constructor, you call <code>parent::__construct()</code> to run the parent class constructor.

intermediate

Can parent be used to access overridden methods?

Yes, <code>parent</code> lets you call the parent class version of a method even if the child class has overridden it.

intermediate

What happens if you use <code>parent</code> in a class without a parent?

Using <code>parent</code> in a class without a parent class causes a fatal error because there is no parent to refer to.

beginner

Example: How to call a parent method named show() inside a child class?

Use <code>parent::show();</code> inside the child class method to call the parent's <code>show()</code> method.

What does parent::methodName() do in PHP?

A Deletes the method <code>methodName</code>

B Calls the method <code>methodName</code> from the child class

C Creates a new method named <code>methodName</code>

D Calls the method <code>methodName</code> from the parent class

parent::methodName() calls the method from the parent class, even if the child class has overridden it.

How do you call the parent constructor inside a child class constructor?

A parent::__construct()

B parent::constructor()

C this->parent()

D super::__construct()

In PHP, the parent constructor is called with parent::__construct().

What error occurs if parent is used in a class without a parent?

A Warning: Undefined variable

B Fatal error: Cannot access parent

C Parse error: Unexpected token

D No error, it works fine

Using parent in a class without a parent causes a fatal error because no parent exists.

Can parent access private properties of the parent class?

A Yes, always

B Only if declared static

C No, private properties are not accessible

D Only if accessed via a method

Private properties are not accessible by child classes, even with parent.

Which keyword is used to refer to the parent class in PHP?

A parent

B super

C base

D this

The keyword parent is used to refer to the parent class in PHP.

Explain how the parent keyword works in PHP and give an example of calling a parent method.

Think about how a child class can reuse code from its parent.

Describe what happens if you try to use parent in a class that does not extend any other class.

Consider what <code>parent</code> means and what happens if it has nothing to refer to.