Class and object

Creating a Class:

To create a class use the class keyword and a name. Class names can be any combination of numbers and letters, although they must not begin with a number.
The code associated with a class must be enclosed within braces.

Class Defination:

<?php
class ClassName {
  // class body
}
?>

For example:
<?php

class Books{

public $name;
public $author;

public function showBook(){
$name="Munna Madan";
echo $name;
}
}
?>

Setting Properties and Methods
In the class body are defined its properties and methods.
        - Properties are variables defined inside the class.
        - Methods are functions created within the class, with the word "function".

The name of the variable (property) and the "function" word must be preceded by a specific attribute that determines the level of access that is allowed for the property or the method to be accessed outside its class. This can be: public, protected, or private.

    public - available in all script
    protected - available to the class itself and to sub-classes that inherit from it
    private - available only inside that class

If no attribute is added, it is considered "public".

Full syntax to create a class is:
<?php
class Class_Name {
  attribute $property1;
  attribute $property2;
  ...

  attribute function Method1() {
    // method code
  }
  attribute function Method2() {
    // method code
  }
  ...
}
?>

Creating Objects:

Once a class is created, to be used in your script, you must instantiate an object of that class. The instance is declared in the PHP script with the new operator, followed by the name of the class and two parentheses.
   Syntax:

$object_Name = new Class_Name();

- $object_Name is the name of the object by which can be used properties and methods of that class.


Now full example of Class and object below:

<?php

class Books{

public $name;
public $author;

function showName(){
    $name="Munna Madan";
    $author="Laxmi Prasad Devkota";
   
    echo "Book named ".$name." was written by".$author;
}
   
}

$obj=new Books(); //creating an object
$obj->showName();// calling function via object

?>

I hope it was not very hard !!!

Object Oriented Programming

PHP is an object- oriented programming language.

What is object-oriented programming (OOP)?

Object-oriented programming(OOP) is a programming language using objects usually instances of a class, consisting of data fields and methods together with their interactions to design applications and computer programs.

Main features of OOP are as below:

 Class and object:
    A class is a group of objects and an object is an instance of a class. It contains the code for properties and methods.


Encapsulation:
    Encapsulation is the ability of an object to protect the data (properties) of a class from outside influences. You can use a class (its properties) through an object instance, without having access to its code.

Inheritance:
    Inheritance is the ability of a class to copy or inherit the properties and methods of a parent class.

Polymorphism:
    Polymorphism is a class ability to do more different things, or use one class or another to achieve the same thing, having similar functions.