Classes Whats the point?

[miles_rich]

I am trying to learn about classes, and have just written this very basic bit of code

<?php

class test_clas
{
	var $var_1;

	function set_values($var_name, $var_value)
	{
		$this->$var_name = $var_value;
	}

	function output($var_name)
	{
		echo $this->$var_name;
	}
}

$test = new test_clas;
$test->set_values('var_1', 'Foo');
$test->output('var_1');
$test->set_values('var_1', 'Bar');
$test->output('var_1');
?>

But i still dont understand what is the point in using them??

Anyone offer any ideas, suggestions?

[rcmehta_14]

I assume that you are aware of Strong features of Object Oriented concept provided by Java and C++.

Well, currently PHP doesn't offer that kind of Strong Class implementation, but still u can use the basic features of classes. They are as follows:

• One can encapsulate an object and it's common properties in a class and use that code in any script that require such object.

For example, suppose you are developing a E-com site that requires an implementation of Cart. Now a user can add OR remove OR edit the items in a cart at any time (using any page of your screen). Therefore to write the same code again and again at each of the screen is tadious and it makes the maintenance more complex. Instead you can define a class of a cart and add function to it for Adding, deleting and mofidying items. This way you can make your work easy.

Although the same thing can be implemented using Function, this approach of using class provides a more idealistic approach that can be more readable.

• More idealistic implementation with Database.
  You can implement the database tables with class declaration for each. and having all db operations as their functions.

These are some basic information about using class. But the most powerful reason is that PHP 5 will be packced with the latest Object Oriented Concept like Private, Public and Protected datatypes as well as functions that you can use like Java and C++. So it is better to have a start using classes right now.

You can find more about Object Oriented concepts at
http://java.sun.com/docs/books/tutorial/java/concepts/

[Wynder]

The truth is, you can probably get by without ever using a class, however, in some situations, it may be easier to use a class -- in addition, it jacks up the professionalism of your code quite a bit by modularizing your code, extending it's reusability.

In the same way that you break repetitive code down into methods or functions, sometimes you're dealing extensively with a single object throughout the course of a page.

It's very hard to explain without posting a full fledged class, but throughout the execution of a single page, your class object can store, reference, and manipulate the data -- for instance, if you have a class file for dealing with MySQL that handles connecting, queries, and fetching results, all of the information can be stored in the class and retreived using syntax like:

$MySQL->connect();
$result = $MySQL->query("SELECT * FROM tblData");
while( $row = $MySQL->fetchRow($result) )
{
   echo key($row) . " => " . current($row) . "<br />";
}

In short, it's a method of organizing data that are similar in functionality and relationship.

[miles_rich]

Cheers very much for that.