php

 

PHP WITH OOPS CONCEPT

Object-oriented programming is a programming model organized around Object rather than the actions and data rather than logic.

Class:

A class is an entity that determines how an object will behave and what the object will contain. In other words, it is a blueprint or a set of instruction to build a specific type of object.

In PHP, declare a class using the class keyword, followed by the name of the class and a set of curly braces ({}).

This is the blueprint of the construction work that is class, and the houses and apartments made by this blueprint are the objects.

Syntax to Create Class in PHP

1. <?php  
2. class MyClass  
3.     {  
4.         // Class properties and methods go here  
5.     }  
6. ?>  

Important note:

In PHP, to see the contents of the class, use var_dump(). The var_dump() function is used to display the structured information (type and value) about one or more variables.

Syntax:

1. var_dump($obj);  

Object:

A class defines an individual instance of the data structure. We define a class once and then make many objects that belong to it. Objects are also known as an instance.

An object is something that can perform a set of related activities.

Syntax:

1. <?php  
2. class MyClass  
3. {  
4.         // Class properties and methods go here  
5. }  
6. $obj = new MyClass;  
7. var_dump($obj);  
8. ?>  

Example of class and object:

1. <?php  
2. class demo  
3. {  
4.         private $a= "hello javatpoint";  
5.         public function display()  
6.         {  
7.         echo $this->a;  
8.         }  
9. }  
10. $obj = new demo();  
11.     $obj->display();  
12. ?>
13. 
    

14. ABSTRACT CLASS

    An abstract class is a mix between an interface and a class. It can be define functionality as well as interface.

    • Classes extending an abstract class must implement all of the abstract methods defined in the abstract class.
    • An abstract class is declared the same way as classes with the addition of the 'abstract' keyword.

    SYNTAX:

    1. abstract class MyAbstract  
    2. {  
    3.     //Methods  
    4. }  
    5. //And is attached to a class using the extends keyword.  
    6. class Myclass extends MyAbstract  
    7. {  
    8.     //class methods  
    9. }  

    Example 1

    1. <?php  
    2. abstract class a  
    3. {  
    4. abstract public function dis1();  
    5. abstract public function dis2();  
    6. }  
    7. class b extends a  
    8. {  
    9. public function dis1()  
    10.     {  
    11.         echo "javatpoint";  
    12.     }  
    13.     public function dis2()  
    14.     {  
    15.         echo "SSSIT";     
    16.     }  
    17. }  
    18. $obj = new b();  
    19. $obj->dis1();  
    20. $obj->dis2();  
    21. ?>  
    22. 
        

    Access Specifiers in PHP

    There are 3 types of Access Specifiers available in PHP, Public, Private and Protected.

    Public - class members with this access modifier will be publicly accessible from anywhere, even from outside the scope of the class.

    Private - class members with this keyword will be accessed within the class itself. It protects members from outside class access with the reference of the class instance.

    Protected - same as private, except by allowing subclasses to access protected superclass members.

    EXAMPLE 1: Public

    1. <?php  
    2. class demo  
    3. {  
    4. public $name="Ajeet";  
    5. functiondisp()  
    6. {  
    7. echo $this->name."<br/>";  
    8. }  
    9. }  
    10. class child extends demo  
    11. {  
    12. function show()  
    13. {  
    14. echo $this->name;  
    15. }  
    16. }     
    17. $obj= new child;  
    18. echo $obj->name."<br/>";     
    19. $obj->disp();  
    20. $obj->show();  
      
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