Constructors and Destructors

Using Constructor to Initialize Objects

As you have seen, you can create objects with the new operators, and then use methods like set_name to the internal data in the object.

function set_name($data)

{

$this->name=$data;

}

in this way, you can initialize the data inside an object before you start working with the object.

   wouldn't it be convenient  if you could both create and initialize an object at the same time?  PHP allow you to do that with constructors, which, as in other languages that support OOP, ARE SPECIAL methods automatically run when an object is created.

       constructors have a special name in PHP -_construct; that is, "construct" preceded by two underscores. Here's and example


function __construct($data)  
{
         .
         .
}

 we can assign that data to the internal name stored in the object like this;

   function __construct($data)  
{
         $this->name=$data;
        
}

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.

Note: Parent constructors are not called implicitly if the child class defines a constructor. In order to run a parent constructor, a call to parent::__construct() within the child constructor is required.

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