Thursday 20 May 2010

What are Constructors and Destructors?

Constructor

void __construct ([ mixed $args [, $... ]] )
PHP 5 allows developers to declare constructor methods for classes. Classes which have a constructor method call this method on each newly-created object, so it is suitable for any initialization that the object may need before it is used. 

<?phpclass BaseClass {
   function 
__construct() {
       print 
"In BaseClass constructor\n";
   }
}

class 
SubClass extends BaseClass {
   function 
__construct() {
       
parent::__construct();
       print 
"In SubClass constructor\n";
   }
}
$obj = new BaseClass();$obj = new SubClass();?>
 
 

Destructor

void __destruct ( void )
PHP 5 introduces a destructor concept similar to that of other object-oriented languages, such as C++. The destructor method will be called as soon as all references to a particular object are removed or when the object is explicitly destroyed or in any order in shutdown sequence. 


<?phpclass MyDestructableClass {
   function 
__construct() {
       print 
"In constructor\n";
       
$this->name "MyDestructableClass";
   }

   function 
__destruct() {
       print 
"Destroying " $this->name "\n";
   }
}
$obj = new MyDestructableClass();?>

 

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