Constructor and Destructor in PHP

Introduction

The constructor and destructor is a feature of Object Oriented Programming (OOP). And this concept is implemented in PHP5. Now in this article, I explain "constructor" and "destructor" separately.

Constructor

The constructor is an "OOP" feature. PHP 5 has OOP capability and gives the authority to developers to declare a constructor method for classes. I will first explain what a constructor is. The answer is "A constructor is a special type of method that is automatically called when you create a new instance of the class". The OOP constructor has a number of advantages, they are:

• Constructors can accept parameters, that are assigned to specific object fields at creation time.
• Constructors can call class methods or other functions.
• Class constructors can call on other constructors, including those from the parent class.
  

Example

In the following code, the parent class (in other words Myclass) has a constructor. It will not be called implicitly because its sub class (in other words Baseclass) defines a constructor (in PHP the parent class constructor is not called implicitly if the child class defines a constructor). Whenever an object of the child class is created. The sub class constructor will be called automatically.

<?php
class Myclass
{
function __construct()
{
print "Parent class constructor.</br>";
}
}

class Baseclass extends Myclass
{
function __construct()
{
parent::__construct();
print " Child Class constructor\n";
}
}

$obj = new Myclass();