PHP Object Oriented Programming

PHP

PHP Object Oriented Programming

Object-oriented programming (OOP) is a technology used for software development. OOP facilitates component programming with its standards. C# is a language based on OOP. There are many objects available in C#, and programs are written using these objects. Additionally, we can write our own class.

OOP has three principles:

Encapsulation
Inheritance
Polymorphism

Encapsulation: It refers to the information and operations about an object. These operations, called methods and properties, reveal the characteristics of the object, such as the color and size of a car.

Inheritance: It is the creation of an object based on another object, with the new object being influenced by the parent object. For example, a computer is composed of parts, and the parts are influenced by the full object of the computer.

Polymorphism: It is the use of a specific operation by multiple objects.

Object-Oriented Programming in PHP

To understand object-oriented programming in PHP, it is necessary to have a thorough knowledge of functions and variables, which are the basic building blocks of PHP.

We use the class command to create a class.

Let's create a file named class.php

<?php
class Computer{ }
?>

Our class is empty. After this, we cannot do anything other than variable declaration and function declaration here. The logic here is that we need to write a function specific to the class we are going to write and call the necessary function where necessary. It would not be appropriate to write a database class and then write a function to produce graphical statistics within it.

<?php
class Computer{
 public $brand, price;
 function defineBrand($newBrand){
  $this->brand = $newBrand;
 }
 function showBrand(){
  return $this->brand;
 }
}
?>

We have created the functions defineBrand() and showBrand(). You can understand from the names what they do. Here, a special reference variable, $this->, is different from general usage. We use the $this-> expression to access a variable and access other functions of the current class.
With $this->brand = $newBrand, we assigned the value of $newBrand to the variable $brand, and with return $this->brand, we return the $brand variable.

Now, let's create an index.php file and include the class.php file.

<?php
include 'class.php';
?>

We only called the class.php file, but we are not using the computer object inside it yet. So let's continue.

<?php
include 'class.php';
$computer = new Computer();
?>

I assigned the computer object to the $computer variable. Think of this variable as a handle; we can hold and control the cup with it.

<?php
include 'class.php';
$computer = new Computer();
$computer->defineBrand('HP');
echo $computer->showBrand();
?>

We defined the brand with the defineBrand function and printed it to the screen with showBrand. We did all of these with the class and its methods.

In PHP, object-oriented programming is generally done like this.
This topic is not limited to these, it's a very deep topic, I just wrote it for introductory purposes.