Classes

Creating Classes and Objects in PHP is similar to C++. Let's see an example of a Car class:

class Car
{
    public $name;            
    public $price;
    public function printInfo(){
        echo "This is a sports car";
    }   
}

Here, 'public' means the variable/method can be directly accessed. Now, to create an object from the class:

$car1 = new Car();           // Object Creation
// Output: This is a sports car
$car1->printInfo();
// Accessing and Defining object properties    
$car1->name = "Lamborgini";
$car1->price = "$200000";

Private Property

The private property can only be accessed and modified through the class's internal methods. Let's see an example of the same class containing a private variable in it.

class Car
{
    private $name;        
    // Class's internal methods    
    public function setName($value){
        $this->name = $value;            // Setting own 'name'
    }   
    public function getName(){
        echo "Car name is " . $this->name;
    } 
}

Here, '$this' refers to the particular object through which setName or getName is being called. Now, let's create an object and interact with a private variable.

$car2 = new Car();        
// $car2->name = "Lamborgini";        // Not Allowed
$car2->setName("Lamborgini");
// Output: Car name is Lamborgini
$car2->getName();

Constructor Function

It is a function that automatically runs when a new object is created. To initialize the object's property easily, we need to define a constructor function in the class as follows:

class Car{
    public $name;            
    public $price;
    // Constructor function 
    public function __construct($name, $price)
    {
        // Set variable of object as specified 
        $this->name = $name;
        $this->price = $price;
    }
}

Now, we can define an object's property when creating it as follows:

$car3 = new Car("Lamborgini", "$200000");
// Output: Lamborgini
echo $car3->name;
// Output: $200000
echo $car3->price;