PHP Object-Oriented Programming

OOP is short for Object-Oriented Programming, a way of structuring a PHP program around classes and objects. Each one carries its own data, called properties, and its own behavior, called methods.

This style pays off as a project grows, because the code stays easier to scale, reuse and maintain.

Procedural code, the traditional alternative, is a list of steps that PHP runs one after another. With OOP, your job shifts: you design the classes and objects, then decide how they work together.

Why choose OOP over procedural code? It brings three main benefits:

• Your program gets a clear, well-defined structure
• Shared logic lives in one place, following the DRY idea ("Don't Repeat Yourself"), so maintaining, changing and debugging the code takes less effort
• You can build fully reusable applications while writing less code and spending less time on development

Tip: DRY simply means avoiding repeated code. When several parts of an application need the same logic, pull it out, keep it in one spot and reuse it from there.

OOP in PHP relies on a handful of ideas that keep code modular, reusable and easy to maintain:

• Classes and Objects - The class is the template, and each object is one separate instance built from it
• Encapsulation - Access modifiers (public, protected, private) let developers decide who may reach an object's internal state
• Inheritance - A new class can take over the properties and methods of a class that already exists
• Abstraction - An abstract class serves as a blueprint for other classes and can't be instantiated by itself
• Interfaces - An interface lists the methods that any class implementing it has to provide

Object-oriented programming rests on two core ideas: classes and objects.

Think of a class as a template. An object is one individual instance made from that template.

A new object receives every property and method its class defines, yet the values held in those properties differ from one object to the next.