Parent keyword behavior in PHP - Mini Project: Build & Apply

Understanding Parent Keyword Behavior in PHP

📖 Scenario: Imagine you are building a simple system to manage different types of vehicles. You want to reuse some common behavior from a base vehicle class and extend it in child classes.

🎯 Goal: You will create a base class with a method, then create a child class that overrides this method but still calls the original method using the parent keyword.

📋 What You'll Learn

Create a base class called Vehicle with a method describe() that returns the string "This is a vehicle."

Create a child class called Car that extends Vehicle and overrides the describe() method.

Inside the Car class's describe() method, call the parent describe() method using the parent keyword and append the string " Specifically, it is a car."

Create an instance of the Car class and print the result of calling its describe() method.

💡 Why This Matters

🌍 Real World

Using inheritance and the parent keyword helps programmers reuse code and extend functionality without rewriting common parts.

💼 Career

Understanding how to use the parent keyword is essential for working with object-oriented PHP code in many real-world projects, such as web applications and frameworks.

1

Create the base class Vehicle

Create a class called Vehicle with a public method describe() that returns the string "This is a vehicle."

PHP

# Create class Vehicle with method describe() returning "This is a vehicle."
# Your code here

Need a hint?

Use class Vehicle {} to create the class and define the method inside it.

2

Create the child class Car

Create a class called Car that extends Vehicle and overrides the describe() method.

PHP

<?php
class Vehicle {
    public function describe() {
        return "This is a vehicle.";
    }
}

# Create class Car that extends Vehicle and overrides describe()
# Your code here

Need a hint?

Use class Car extends Vehicle {} and define describe() inside it.

3

Use parent keyword inside Car's describe method

Inside the Car class's describe() method, call the parent describe() method using parent::describe() and append the string " Specifically, it is a car." to the returned value.

PHP

<?php
class Vehicle {
    public function describe() {
        return "This is a vehicle.";
    }
}

class Car extends Vehicle {
    public function describe() {
        # Call parent describe() and append " Specifically, it is a car."
        # Your code here
    }
}

Need a hint?

Use parent::describe() to call the base class method inside the child method.

4

Create Car instance and print description

Create an instance of the Car class called $myCar and print the result of calling its describe() method using echo.

PHP

<?php
class Vehicle {
    public function describe() {
        return "This is a vehicle.";
    }
}

class Car extends Vehicle {
    public function describe() {
        return parent::describe() . " Specifically, it is a car.";
    }
}

# Create instance of Car and print description
# Your code here

Need a hint?

Use $myCar = new Car(); and echo $myCar->describe(); to show the message.