Oops stands for object-oriented programming language. It is also known as a procedural programming language. It is a programming approach or paradigm that gives us prime consideration of the data and its associated functions. with the help of we can perform operations on data.

It allows you to structure your code more organized and modularly, making it easier to manage and maintain.

It has several advantages.

1. It is faster and easier to execute.
2. It provides us with the standard structure of programming language.
3. It helps us to debug, make it easy to maintain, modify the code and work on the DRY principle ( Don’t Repeat Yourself ).
4. It reduces the code with a shorter time.
5. It provides higher security and less exposure to the data.
6. The object-oriented is used to describe the application’s functionality.

What is a class in PHP?

In PHP, we can define a class by using the “class” keyword. It encapsulates the properties (attributes) and behaviours (methods).

The class is the blueprint or a set of instructions to build a specific type of object.

1. The class is a template for objects.
2. The class is an entity that is used to determine how an object will behave and what the object will contain.
3. The class is used to hold the objects along with their behavior and properties.
4. It is a programmer-defined data type, that includes local functions as well as local data. You can think of a class as a template for making many instances of the same kind (or class) of object.

Example1

<?php
class Car {
  public function name() {
     echo " This is the Simple Example of class";
  }
}
$obj= new Car;
$obj->name();
?>

Output

This is a Simple Example of a class

Example 2

<?php
class Fruit {function name($parm) {
 echo $parm;
  }
}
$apple = new Fruit();
echo $apple->name("Mango");
?>

Output

Mango

Example 3

<?php
class Car{ 
    private $name= "My Fav Car Hyundai Creta"; 
    public function display(){ 
       echo $this->name; 
    } 
} 
$obj = new Car(); 
$obj->display(); 
?>

Output
My Fav Car Hyundai Creta

What is an object in PHP?

In PHP, objects can be related to the entities in real life It considers everything that we can see around us, as an object that has some attributes. An object is an instance of a class. It's created from a class blueprint using the new keyword followed by the class name, optionally passing arguments to the constructor if it's defined. Objects have properties (attributes) and methods defined by their class.

Multiple objects can be created from the same class, each having its own set of property values. Objects allow you to work with specific instances of a class, allowing for data encapsulation and code reuse.

1. An object is an instance of class.
2. Objects have properties (attributes) and methods defined by their class.
3. An object is something that is used to perform a set of related activities.
4. We can define a class once and then create one or more objects that belong to it.
5. Multiple objects can be created from the same class, each having its own set of property values.
6. An Object is an individual instance of the data structure defined by a class.
7. Class methods and properties can be accessed directly through object instances.
8. We we use the connector (Dot operator->) symbol to connect objects to their properties or methods.

<?php  
class Office  
{  
  // Class properties
  // methods go here  
}  
$obj = new Office;  
var_dump($obj);  
?

<?php
class Office{
  public function Chair_name(){
      echo "This is Desk Chair"."&lt;br&gt;";
  }
  public function price(){
     echo "RS- 500";
  }
}
$obj = new Office();
$obj-&gt;chair_name();
$obj-&gt;price();
?>

<?php  
class Room  
{  
    private $name= "Kitchen Room";  
    public function display(){  
        echo $this-&gt;name;  
    }  
}  
$obj = new Room();  
$obj-&gt;display();  
? > 

<?php
class Car{
    function CarModel(){
        echo "This is the CarModel function. It will automatically invoke";
    }
    function Car(){
        echo "User Defined Constructor (Class name and function Car() name is same )"."<br>";
    }
}
$obj= new Car();
$obj->CarModel();
?>

<?php
class Car{
    function CarName(){
        echo "Car Name- Thar";
    }
    function __construct(){
        echo "This is predefined constructor"."<br>";
    }
}
$obj= new Car();
$obj->CarName();
?>

<?php
class Car{
    public $name;
    function __construct($name){
        $this->name = $name;
    }
    function get_name(){
        return $this->name;
    }
}
$obj= new Car("THAR");
echo $obj->get_name();
?>

<?php
class Car {
    public function __construct() {
        echo "Constructor called"."<br>";
    }
    public function __destruct() {
        echo "Destructor called";
    }
}
$obj = new Car(); // Output: Constructor called
unset($obj);         // Output: Destructor called
?>

<?php
class Car {
  public $name;
  public $color;
  function __construct($name) {
    $this->name = $name;
  }
  function __destruct() {
    echo "My Car name is : {$this->name}.";
  }
}
$obj = new Car("Thar");
?>

<?php  
    class car{  
    public function car(){  
       echo "User defined constructor1"."<br>";  
       }  
    }  
    class car2 extends car{  
    public function __construct(){  
       echo parent::car();  
       echo "User Defined Extended constructor2"."<br>";  
    }  
    public function __destruct(){  
      echo "Destroy";  
    }  
}  
$obj= new car2();  
?>  

    <?php
    class Car {
        public $name;
        protected $color;
        private $Model;
    }
    $obj = new Car();
    echo $obj->name = 'THAR'; // OK
    echo $obj->color = 'RED'; // ERROR
    echo $obj->weight = 'LX Hard Top trim'; // ERROR
    ?>

<?php  
class Car{  
  public $name="RED THAR";  
    function display(){  
        echo $this->name."<br/>";  
    }
}  
class Model extends Car{  
  function show(){  
      echo $this->name;  
     }  
  }    
$obj= new Model;  
echo $obj->name."<br>";    
$obj->display(); 
$obj->show();  
?>

   <?php
    class Test{
        protected $a=200;
        protected $b=300;
            function add(){
                echo "Addition of (A+B): ".$sum=$this->a+$this->b."<br/>";
            }      
        }  
        class childtest extends test{
            function sub(){
                echo "Subtraction of (A-B): ".$sub=$this->a-$this->b."<br/>";
            }
        }  
        $obj= new childtest;
        $obj->add();
        $obj->sub();
    ?>  

<?php
class Car{
    private $name="THAR CAR";
    private function show(){
        echo "This is private method of parent class";
    }
}  
class Model extends Car{
   function show1(){
       echo $this->name;
   }
}  
$obj= new Model();
$obj->show();
$obj->show1();
?>

class parents{  
public $name="Thar";
protected $Model="Thar-02913";
private $price=50000;
public function show(){
    echo "Welcome : ".$this->name."<br/>";
    echo "Profile : ".$this->profile."<br/>";
    echo "Salary : ".$this->price."<br/>";
    }
}  
class childs extends parents{  
     public function show1(){
        echo "My New Car : ".$this->name."<br/>";
        echo "Model : ".$this->profile."<br/>";
        echo "Price : ".$this->salary."<br/>";
     }
}  
$obj= new childs;  
$obj->show1();
?>

<?php
class parents{  
public $name="Thar";
protected $model="Thar-02913";
private $price=50000;
public function show(){
    echo "Welcome : ".$this->name."<br/>";
    echo "Profile : ".$this->model."<br/>";
    echo "Salary : ".$this->price."<br/>";
    }
}  
class childs extends parents{  
   public function show1(){
        echo "My New Car : ".$this->name."<br/>";
        echo "Model : ".$this->model."<br/>";
        echo "Price : ".$this->salary."<br/>";
   }
}  
$obj= new childs;  
$obj->show1();
?>

<?php  
class car{  
   public $name;  
   public $price;  
   function __construct($n, $p)  {  
        $this->name=$n;  
	$this->price=$m;  
   }  
   public function setPrice($pr){  
      $this->pr=$pr;  
   }  
   public function display(){  
      echo  "We have Kids Toy : ".$this->name."<br/>";  
      return $this->color=$this->pr;   
   }  
}     
// Create a Car object and set Car name, price
$obj=new car("THAR",5000000); 

// Update the car price setPrice() method
$obj->setPrice(900000);  

// Display the updated Price
echo "Price: ".$obj->display(); 
?>

<?php
class calculator{
    var $x=100;
    var $y=50;
    function sum(){
        $res=$this->x+$this->y;
        echo "Addition (X+Y): ".$res."<br/>";
    }
    function sub(){
        $res=$this->x-$this->y;
        echo "Subtraction(X-Y): ".$res."<br/>";
    }
    function mult(){
        $res=$this->x*$this->y;
        echo "Multiplication (X*Y): ".$res."<br/>";
    }
    function div(){
        $res=$this->x/$this->y;
        echo "Division(x/y) : ".$res."<br/>";
    }
}
$obj= new calculator( );
$obj->sum();
$obj->sub();
$obj->mult();
$obj->div();
?>

<?php
class Parent {
    public $name;
    public function __construct($name) {
        $this->name = $name;
    }  
    public function sound() {
        return "Some generic sound";
    }
}
class Dog extends Animal {
    public function sound() {
        return "Woof!";
    }
}
$dog = new Dog("Rex");
echo $dog->name . " says " . $dog->sound();
?>

<?php
class Car {
  public $name;
  public $color;
  public function __construct($name, $color) {
    $this->name = $name;
    $this->color = $color;
  }
  public function intro() {
    echo "We can travel with  {$this->name} and Its color is {$this->color}";
  }
}
// Airplane is inherited from Car
class Airplane extends Car{
  public function message() {
    echo "You can travel with Airplane- Boeing 747"."<br>";
  }
}
$strawberry = new Airplane("Thar", "red");
$strawberry->message();
$strawberry->intro();
?>

<?php
   class Animal {
    public function sound() {
        return "Some generic sound";
    }
}
class Dog extends Animal {
    public function sound() {
        return "Woof!";
    }
}
class GermanShepherd extends Dog {
    public function sound() {
        return "Woof Woof!";
    }
}
$gs = new GermanShepherd();
echo $gs->sound(); 
?>

<?php
class Animal {
    public function sound() {
        return "Some generic sound";
    }
}
class Dog extends Animal {
    public function sound() {
        return "Woof!";
    }
}
class Cat extends Animal {
    public function sound() {
        return "Meow!";
    }
}
$dog = new Dog();
$cat = new Cat();
echo $dog->sound(); 
echo $cat->sound(); 
?>