OOP Concepts in PHP

OOP Concepts

• OOP considers everything in the world as an object, which is an entity that holds its own properties (data) via variables and behaviors (functions) via methods.

Classes & Objects

• A class is the blueprint/template that is used to hold objects along with their behavior and properties.
• An object is simply an instance/occurrence of the class.
• A class can have properties like make, color, year, speed limit, etc.
• Objects inherit all the properties and behaviors from the class, but each object will have different values for the properties.

Defining a PHP Class

• A class is defined by using the class keyword, followed by the name of the class and a pair of curly braces ({}).
• The class name should start with a letter, cannot be a PHP reserved word, and cannot contain spaces.
• All properties and methods go inside the curly braces.

Adding Properties & Methods to a Class

• Properties are added to the class by placing variables inside it.
• Methods are defined using the function keyword before the name of the function.
• Properties and methods can have one of the three visibility modifiers: public, private, and protected.
• If a method is defined without any visibility modifier, it defaults to public.

Calling Member Functions

• After creating an object, you can use it to call the member functions or assign values to the data members (property) of that class.
• To access a property, you use the object operator (->).
• To call a method, you also use the object operator (->).