Defining a class

Learn to define a class with the class keyword.

Defining a class

A class is a template used to create objects. In PHP a class starts with the class keyword, followed by the class name and a body in curly braces.

Example: class User { }. Here User is the class name; the body is empty for now. The class name must start with a letter or underscore. Defining a class does not run it; it only prepares the template.

Class name and body

Class names must start with a letter or underscore; they cannot start with a digit. PHP is case-sensitive, so User and user are different classes. Names like User, Book or Product that start with an uppercase letter and are singular are a good habit.

The body is the area between the curly braces. We will add properties and methods to it; for now it can be empty. An empty body can be written as { }.

Exercise Define the User class

Define a class named User (leave the body empty for now). After the class, write echo "User class defined" . "\n";.

Show example solution

Define with class User { } then write echo after the class.
Example solution:
<?php
// Define the User class
class User {
}
echo "User class defined" . "\n";

Test yourself

Which is a valid class definition?
- User class { }
- class User { }
- function User { }
- new User { }
Show answer

class User { } — Correct. The class keyword, the class name and curly braces form the body.
Complete the class definition
```
____ User {
}
```
Show answer
```
class User {
}
```
Match the parts of a class

class

Keyword
User

Class name
{ }

Body

Next lesson: Defining properties

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies