Constructor and encapsulation in php
- 1. B-Tech CSE 6th 13/NR/UT/CS005 Submitted by :- Shivani Soni Submitted to :- Shivani Dhiman
- 2. PHP is an open source , server-side scripting language. PHP is used to generate dynamic web pages. Originally created by Rasmus Lerdorf in 1994, the PHP reference implementation is now produced by The PHP Group.PHP originally stood for Personal Home Page , but it now stands for Hypertext Preprocessor
- 3. PHP scripts reside between reserved PHP tags . This php tags allows the programmer to embed php scripts with in HTML pages.
- 4. Free Multi OS Support(like linux,windows,OSX) Easier to fix problem Easy to understand Speed Object oriented Compatible with many databases(SQL,MySQL) Simple efficient Secure flexible familiar
- 5. PHP is also OOP language as it also based on the concepts of object and classes. PHP also uses the object oriented concepts like encapsulation , inheritance , polymorphism , data abstraction and constructors.
- 6. Class-: classes are the "blueprints“ for an object and the actual code that defines the properties and methods . and the class is declared with in the tags. Objects-: An object is an instance of a class. Any number of instances of a class can be created. <?php class pen { } ?>
- 7. <?php Class house { Public $name=“Soni”; Public $age=47; Function hello() { Echo “Hello world”; } $h=new house(); $g=new house(); Echo $h->name . “is” .$h->age .”year old”; Echo $g->hello () ?> The output is-:soni is 47 year old hello world
- 8. Define:-Encapsulation is just wrapping of data in single unit also we can say hiding the information of essential details . Or we can say that it is the process of hiding the data of the object from outside world and accessed to it is restricted to members of the class. Example:- Let You have a mobile phone…there it some interface which help You to interact with cell phone and you can uses the services of mobile phone. But the actually working in cell phone is hide. You don’t know how it works internally.
- 9. <?php class App { private static $_user; public function User( ) { if( $this->_user == null ) { $this->_user = new User(); } return $this->_user; } }
- 10. class User { private $_name; public function __construct() { $this->_name = “Shivani"; } public function GetName() { return $this->_name; } } $app = new App(); echo $app->User()->GetName(); ?>
- 11. If a class name and function name will be similar in that case function is known as constructor. constructor is special type of method because its name is similar to class name . constructor automatically calls when object will be initializing. There are two types of constructor 1) user defined constructor 2) predefined constructor
- 13. Note:-here we have called testA() method but we didn’t call A() method because it automatically called when object is initialized.
- 14. PHP introduce a new functionality to define a constructor i.e __construct(). By using this function we can define a constructor. it is known as predefined constructor. __construct() are also known as magic function in PHP.
- 17. <?php class BaseClass { function __construct() { echo "Shivanin"; } } class SubClass extends BaseClass { function __construct() { parent::__construct(); echo “sonin"; } } $obj = new BaseClass(); $obj = new SubClass(); ?>