Classes & Objects in PHP

Introduction

In Object-Oriented Programming (OOP), classes and objects are the foundation of everything. Understanding these two concepts clearly will make the rest of OOP much easier to learn.

In simple terms, a class is a blueprint, and an object is a real instance created from that blueprint. In this tutorial, you will learn what classes and objects are in PHP, how to create them, and how they work together.

What is a Class in PHP?

A class is a blueprint or template used to create objects.
It defines properties (variables) and methods (functions) that an object will have.

Think of a class as a design, not a real thing. It does not represent a real thing by itself — it only defines what the object will look like and what it can do.

Example:
A class called User defines:

• name
• email
• login behavior

What is an Object in PHP?

An object is a real instance of a class.

If a class is a blueprint of a house,
then an object is the actual house built from that blueprint.

You can create multiple objects from the same class.

Creating a Class in PHP

Here is a simple example of a class:

<?php
class User {
    public $name;
    public $email;

    public function sayHello() {
        echo "Hello, welcome!";
    }
}
?>

Explanation:

• class User → defines a class
• $name, $email → properties
• sayHello() → method

Creating an Object from a Class

To use a class, we create an object using the new keyword.

<?php
$user1 = new User();
?>

Now $user1 is an object of the User class.

Accessing Properties and Methods

You can access properties and methods using -> operator.

<?php
$user1 = new User();
$user1->name = "Divyesh";
$user1->email = "div@example.com";

echo $user1->name;
$user1->sayHello();
?>

The $this Keyword

$this refers to the current object inside a class.

It is used to access:

• properties
• methods

Example:

<?php
class User {
    public $name;

    public function setName($username) {
        $this->name = $username;
    }

    public function getName() {
        return $this->name;
    }
}
?>

Using $this with Object

<?php
$user = new User();
$user->setName("Divyesh");

echo $user->getName();
?>

Multiple Objects from One Class

<?php
$user1 = new User();
$user2 = new User();

$user1->setName("Amit");
$user2->setName("Rahul");

echo $user1->getName();
echo $user2->getName();
?>

Each object has its own data, even though the class is the same.

Real-World Analogy

Let’s understand this with a simple example:

• Class → Car blueprint
• Object → Actual car
• Properties → Color, speed
• Methods → Start(), Stop()

You can manufacture many cars from the same blueprint. Each car has its own color and speed but follows the same design.

Similarly, a class defines structure, and objects represent real entities based on that structure.

Why Classes & Objects are Important?

They help you:

• Organize code properly
• Avoid repetition
• Represent real-world entities
• Build scalable applications
• Reduce repetition
• Write reusable logic

Almost all modern PHP applications use classes and objects.

Common Mistakes Beginners Make

• Forgetting to use the new keyword
• Using . instead of -> for accessing properties
• Forgetting to declare properties before using them
• Confusing class name with object variable

Practice small examples to avoid these mistakes.

Practical Task

Create a class named Car with properties like brand and color.
Add a method called start() that prints a message.
Create two objects from this class and assign different values to each object.

Observe how both objects use the same class but store different data.

Summary

• A class is a blueprint or template
• An object is an instance of a class
• Properties store data
• Methods define behavior
• Multiple objects can be created from a single class

Understanding classes and objects is essential before learning constructors, inheritance, and other advanced OOP concepts.

In the next tutorial, we’ll learn about Constructors & Destructors in PHP.