PHP What is OOP

Last modified on: October 19, 2024

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<h3>What is OOP in PHP?</h3>
<p>OOP (Object-Oriented Programming) is a programming paradigm based on the concept of "objects," which can contain data in the form of properties (attributes) and code in the form of methods (functions). OOP is a way to structure your code that makes it modular, reusable, and scalable.</p>
<p>In PHP, OOP provides a more structured approach to programming than procedural coding by organizing code into classes and objects. It is widely used in modern PHP frameworks like Laravel and Symfony.</p>
<hr />
<h3>Key Concepts of OOP in PHP</h3>
<ol>
<li><strong>Class</strong>: A blueprint for objects. It defines properties and methods that objects created from the class will have.</li>
<li><strong>Object</strong>: An instance of a class. Objects have their own unique values for properties defined by the class.</li>
<li><strong>Properties</strong>: Variables that belong to an object.</li>
<li><strong>Methods</strong>: Functions that belong to an object and define its behavior.</li>
<li><strong>Constructor</strong>: A special method that is automatically called when an object is instantiated.</li>
</ol>
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<h3>Example: Basic OOP in PHP</h3>
<p>Here&rsquo;s a simple example to understand how classes and objects work in PHP.</p>
<h4>Example: Defining a Class and Creating Objects</h4>
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<pre class="language-php"><code>class Car {
    // Properties
    public $brand;
    public $model;

// Constructor
    public function __construct($brand, $model) {
        $this-&gt;brand = $brand;
        $this-&gt;model = $model;
    }

// Method
    public function getCarInfo() {
        return "This car is a " . $this-&gt;brand . " " . $this-&gt;model;
    }
}

// Creating an object (an instance of the class)
$car1 = new Car("Toyota", "Corolla");
echo $car1-&gt;getCarInfo(); // Output: This car is a Toyota Corolla</code></pre>
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<h3>Main Principles of OOP in PHP</h3>
<ol>
<li>
<p><strong>Encapsulation</strong>: Encapsulation is about bundling the data (properties) and methods that work on that data into a single unit, the object. It also restricts direct access to some of an object&rsquo;s properties and methods.</p>
<h4>Example: Encapsulation</h4>
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<pre class="language-php"><code>class Person {
    private $name;

public function setName($name) {
        $this-&gt;name = $name;
    }

public function getName() {
        return $this-&gt;name;
    }
}

$person = new Person();
$person-&gt;setName("Alice");
echo $person-&gt;getName(); // Output: Alice</code></pre>
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</li>
<li>
<p><strong>Inheritance</strong>: Inheritance allows a class (child class) to inherit properties and methods from another class (parent class), enabling code reuse.</p>
<h4>Example: Inheritance</h4>
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<pre class="language-php"><code>class Vehicle {
    public $make;
    public $year;

public function start() {
        return "Vehicle started";
    }
}

class Car extends Vehicle {
    public $model;

public function getCarInfo() {
        return $this-&gt;make . " " . $this-&gt;model . " (" . $this-&gt;year . ")";
    }
}

$car = new Car();
$car-&gt;make = "Honda";
$car-&gt;model = "Civic";
$car-&gt;year = 2020;
echo $car-&gt;getCarInfo(); // Output: Honda Civic (2020)</code></pre>
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</li>
<li>
<p><strong>Polymorphism</strong>: Polymorphism allows objects of different classes to be treated as objects of a common parent class. It also allows child classes to define their own behavior while inheriting from a parent class.</p>
<h4>Example: Polymorphism (Method Overriding)</h4>
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<pre class="language-php"><code>class Animal {
    public function sound() {
        return "Some sound";
    }
}

class Dog extends Animal {
    public function sound() {
        return "Bark"; // Overriding parent method
    }
}

$dog = new Dog();
echo $dog-&gt;sound(); // Output: Bark</code></pre>
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</li>
<li>
<p><strong>Abstraction</strong>: Abstraction is the concept of hiding the complex details and showing only the essential features of an object.</p>
<h4>Example: Abstract Class</h4>
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<pre class="language-php"><code>abstract class Shape {
    abstract public function area();
}

class Circle extends Shape {
    private $radius;

public function __construct($radius) {
        $this-&gt;radius = $radius;
    }

public function area() {
        return 3.14 * $this-&gt;radius * $this-&gt;radius;
    }
}

$circle = new Circle(5);
echo $circle-&gt;area(); // Output: 78.5</code></pre>
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</li>
</ol>
<hr />
<h3>Benefits of OOP in PHP</h3>
<ul>
<li><strong>Code Reusability</strong>: Through inheritance, you can create a parent class and then extend its functionality without duplicating code.</li>
<li><strong>Modularity</strong>: Code can be divided into separate objects (modules), making it easier to manage.</li>
<li><strong>Maintainability</strong>: OOP improves the structure of the code, making it easier to debug and maintain over time.</li>
<li><strong>Scalability</strong>: OOP makes it easier to scale and extend applications, especially for large projects.</li>
</ul>
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<h3>&nbsp;</h3>
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