Constructor inheritance in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is constructor inheritance in PHP?

Constructor inheritance means a child class can use the constructor method of its parent class to set up initial values or states.

beginner

How do you call a parent class constructor inside a child class in PHP?

You use <code>parent::__construct()</code> inside the child class constructor to run the parent constructor.

intermediate

What happens if a child class defines its own constructor but does not call <code>parent::__construct()</code>?

The parent constructor will NOT run automatically. The child constructor overrides it, so you must call the parent constructor explicitly if needed.

beginner

True or False: If a child class does not define a constructor, it automatically inherits the parent's constructor in PHP.

True. The child class will use the parent's constructor if it does not have its own.

beginner

Why might you want to call the parent constructor inside a child constructor?

To make sure the parent class sets up its part of the object correctly before the child adds or changes anything.

In PHP, how do you call the parent class constructor from a child class?

A parent::__construct()

B super()

C this->__construct()

D base::__construct()

In PHP, parent::__construct() calls the parent class constructor.

If a child class has no constructor, what happens when you create an object of that child class?

A The child class constructor runs

B No constructor runs

C An error occurs

D The parent's constructor runs automatically

If the child class has no constructor, PHP uses the parent's constructor automatically.

What happens if a child class defines a constructor but does NOT call parent::__construct()?

A Only the parent constructor runs

B Both parent and child constructors run automatically

C Only the child constructor runs

D PHP throws an error

The child constructor overrides the parent constructor, so only the child constructor runs unless you call parent::__construct() explicitly.

Why is constructor inheritance useful?

A It lets child classes reuse setup code from parent classes

B It prevents child classes from having constructors

C It makes PHP run faster

D It disables object creation

Constructor inheritance helps child classes reuse the parent's setup code, avoiding repetition.

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

A this

B parent

C base

D super

The keyword parent refers to the parent class in PHP.

Explain how constructor inheritance works in PHP and how to properly use it in a child class.

Think about when the parent's constructor runs and how to call it explicitly.

Describe a real-life example where calling a parent constructor from a child class is important.

Imagine building a car where the base car sets wheels and engine, and the child adds special features.