PHP Constructors and destructors

A constructor is a special method in a class. It is used to auto initialize property, methods, etc while using a class’s object. This constructor method is applicable to every method of consists of class.

The constructor function named __construct(), If the current class extending a parent class and It want to use the construct method of the parent class. Then It uses parent::__construct() with-in child class.
 

Using constructor on a simple class

<?php

class BaseClass {
    function __construct() {
        print "In BaseClass constructor\n";
    }
}

// In BaseClass constructor
$obj = new BaseClass();

?>

Using constructor with a parent class

<?php

class SubClass extends BaseClass {
    function __construct() {
        parent::__construct();
        print "In SubClass constructor\n";
    }
}

// In BaseClass constructor
// In SubClass constructor
$obj = new SubClass();

?>

Warning:

Old style constructors are DEPRECATED in PHP 7.0 and will be removed in a future version. You should always use __construct() in new code.

Unlike with other methods, PHP will not generate an E_STRICT level error message when __construct() is overridden with different parameters than the parent __construct() method has.

Destructor

PHP also provides destructor methods alike other object-orient programming languages, I.e Java, C++, etc. The destruct method is used to stop the auto initialized resource of class.

Parent destructor is not automatically run. To run parent destructor explicitly call parent::__destruct() in destructor method.

Note:

• If HTTP headers already sent in the script then destructor will be shutdown.

• While you will try to use exception handling with a destructor, It will cause a fatal error during script execution.