Interface vs abstract class vs trait in PHP - Hands-On Comparison

Interface vs Abstract Class vs Trait in PHP

📖 Scenario: Imagine you are building a simple system for different types of vehicles. Each vehicle can start and stop, but some vehicles have extra features like flying or floating. You want to organize your code so that you can reuse common parts and also force certain methods to be created.

🎯 Goal: You will create an interface, an abstract class, and a trait in PHP to understand how they differ and how to use them together.

📋 What You'll Learn

Create an interface called VehicleInterface with methods start() and stop()

Create an abstract class called Vehicle that implements VehicleInterface and has a property $speed and a method getSpeed()

Create a trait called Flyable with a method fly()

Create a class Car that extends Vehicle and implements the start() and stop() methods

Create a class FlyingCar that extends Vehicle, uses the Flyable trait, and implements the start() and stop() methods

Print messages to show the behavior of Car and FlyingCar

💡 Why This Matters

🌍 Real World

In real software, interfaces, abstract classes, and traits help organize code for things like vehicles, users, or devices, making it easier to add new types without rewriting everything.

💼 Career

Understanding these concepts is important for PHP developers to write clean, reusable, and maintainable code in professional projects.

1

Create the VehicleInterface

Create an interface called VehicleInterface with two methods: start() and stop().

PHP

// Your code here

Need a hint?

An interface defines method names without code. Use the interface keyword.

2

Create the abstract Vehicle class

Create an abstract class called Vehicle that implements VehicleInterface. Add a protected property $speed set to 0 and a public method getSpeed() that returns $speed.

PHP

<?php
interface VehicleInterface {
    public function start();
    public function stop();
}

// Your code here

Need a hint?

Use abstract class and implements keywords. Define property and method inside the class.

3

Create the Flyable trait

Create a trait called Flyable with a public method fly() that prints "Flying!".

PHP

speed;
    }
}

// Your code here

Need a hint?

Use the trait keyword and define the method inside it.

4

Create Car and FlyingCar classes and show output

Create a class Car that extends Vehicle and implements start() and stop() methods that print "Car started" and "Car stopped" respectively. Create a class FlyingCar that extends Vehicle, uses the Flyable trait, and implements start() and stop() methods that print "FlyingCar started" and "FlyingCar stopped" respectively. Then create objects of Car and FlyingCar, call their start(), fly() (only for FlyingCar), and stop() methods, printing each result on a new line.

PHP

speed;
    }
}

trait Flyable {
    public function fly() {
        echo "Flying!\n";
    }
}

// Your code here

Need a hint?

Remember to use extends for inheritance, use for traits, and implement all interface methods.