How Can We Access the Methods and Properties of a Class in PHP?

PHP inheritance

Inheritance is a way to create specialized classes from existing classes. PHP allows you to inherit from multiple parent classes, giving you the ability to build a hierarchy of similar objects.

Here's an example:

```php

class Person {

public $name = null; public $age = null; public function __construct($name, $age) { $this->_setName($name); $this->_setAge($age); } private function _setName($name) { if (is_null($this->name)) { throw new \Exception('The person must be given a name.'); } elseif (!is_string($this->name)) { throw new \Exception('The person must have a string ID.'); } elseif (!strlen($this->name)) { throw new \Exception('The person must have a valid length of name.'); } elseif ($this->age && !$this->age > 0) { throw new \Exception('The child cannot be younger than 0 years old!'); } elseif ($this->age && !$this->age < 25) { throw new \Exception('The child cannot be older than 25 years old!'); } if (strpos(strtolower(substr(PHP_OS, 0 , 3)), 'win') === false) { throw new \Exception("This script will only run on Windows systems"); } $temp = @unserialize(file_get_contents("php://stdin")); if ($temp['error']){ // TODO: Handle error return false; } // ...more code... ```

Static properties and methods

A static property is a property of a class that does not belong to any object. It is accessed through the class name.

A static method is a method of a class that cannot be called on an instance of that class, but rather on the class itself. Static methods are accessed through the name of the class, not by using an object reference or $this reference like you do in normal non-static methods.

This keyword

The this keyword can be used to access the current object. It can also be used to access its methods and properties in a method or constructor.

The following example shows you how this keyword is used:

class TestClass {

public function sayHello() {

$this->hello = 'Hello!';

Abstract classes

In PHP, there is a way to make a class abstract. An abstract class is a class that cannot be instantiated. This means we can't use it to create objects but it can have other methods and properties.

For example:

<?php

class Car {

public function drive() {

}

}

Final keyword in PHP

The final keyword in PHP is used to prevent inheritance. You can use the final keyword to make sure that the class cannot be inherited. The final keyword also prevents overriding of methods and properties. A method or property marked as final cannot be overridden by any child class; it should be a member of Object, Array or Iterator classes only.

The syntax for using final keyword is:

``final = ``

Getters and setters

Getters and setters are methods that allow you to access the value of an object's properties. They're often used to create a consistent API for accessing data, and they can also be used to control access to the data.

The following example shows how getters and setters work with classes:

class Car {

public $model; // The name of your car model (e.g., "Sedan")

public $year; // The year your car was built (e.g., 2022)

// Getters and setters here...

You can access the members of a class by using instances, static properties and methods, and abstract classes.

In PHP, you can access members of a class by using instances, static properties and methods, and abstract classes.

When you are working with objects from the same class, you will use instances. Instances are created when you instantiate an object using the new keyword. If you don’t want to create instances of a particular class or if there is no need for them in your program then it is recommended that you use static properties or methods instead.

In PHP 5 and above versions, there are two ways to use static properties:

• With a double underscore prefix (e.g., __construct()). This method allows developers to access all static properties without having to specify an instance first; however, it also means that we cannot create subclasses that override these methods without explicitly declaring them as ‘final’ so that they cannot be overwritten in subclasses which would otherwise break their functionality!

• Without any prefixes at all – this lets us initialize some values before creating our first instance (if necessary) but still allows us complete control over what goes into each one individually later on down the line...