OOP Object-Oriented Programming

Advantages of using OOP: Is faster and easier to execute. Provides a clear structure for the programs. Helps to keep code DRY "Don't Repeat Yourself" and makes code easier to maintain, modify, and debug. Makes it possible to create fully reusable applications with less code and shorter development time. Define a Class: A class is defined by using the class keyword, followed by the name of the class and a pair of curly braces {} . All its properties and methods go inside the braces. Delegation: Delegation means that you use an object of another class as an instance variable. We can create multiple objects from a class. Each object has all the variables and functions defined in the class. An object of a class is made using the new keyword. Note: The $this keyword refers to the current class and is only available inside methods. __construct() function: Automatically runs at the beginning of the class. __destruct() function: Automatically runs at the end of the class. Encapsulation: The wrapping up of data and methods is a protection mechanism for the variables and functions inside the class. Access Modifier: Public: Variables or functions can be accessed from everywhere. Private: Variables or functions can ONLY be accessed inside the class. Protected: Variables or functions can be accessed inside the class and by child classes that extend from the parent class. Constants: It can’t be changed once it is declared. Declared inside a class with the const keyword. It is recommended to name the constants in all uppercase letters . Access outside the class by using the class name followed by the scope resolution operator :: . Access a constant inside the class by using the self keyword. Static Functions and Variables: Static functions or variables can be called directly - without creating an instance of the class first. Static functions or variables are declared with the static keyword. To access a static function or variable, use the class name , double colon :: , and the fu