Object-Oriented Programming (OOP) in PHP

Object-Oriented Programming (OOP) is a programming approach that organizes code using classes and objects, making programs modular, reusable, secure, and easy to maintain.

Exam Definition: OOP is a programming paradigm based on the concept of objects which contain data and methods.

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Classes, Objects, Fields, Properties, Methods

Class

A class is a blueprint or template used to create objects.

class Student {
   public $name;
   public function show() {
      echo "Student Class";
   }
}

Object

An object is an instance of a class.

$s1 = new Student();
$s1->show();

Fields / Properties

Variables declared inside a class are called properties (or fields).

public $name;
private $age;

Methods

Functions declared inside a class are called methods.

public function display() {
   echo $this->name;
}

Exam Line: Properties store data and methods define behavior.