How to Add Parameters to Your PHP Class (Constructor Tutorial)

There are not many tutorials on this other than forum posts. The other day, I was searching for "PHP class add parameters" and nothing came up. It was after reading about how to use PHP class constructors that I was actually able to do this. Constructors define how your class is created and can also have parameters. In essence, they make your classes modifiable.
Constructors can be used for a variety of reasons. In my case, I needed it to connect to a database. Instead of using a function and a class, I combined my function into a constructor. For this reason, I will show you how to use a class to connect to a database as an example.

Step 1: Create the __construct() function in your class

I named my class icdb. You can, however, name it anything you want.

class icdb {
	function __construct() {
	}
}

Step 2: Add parameters to the __construct() function

Add parameters to this like any other function.

function __construct($db_host, $db_user, $db_pass, $db_name) {
}

Step 3: Make your function

Do whatever you want. Here I am connecting to a database, obviously.

function __construct($db_host, $db_user, $db_pass, $db_name) {
	global $db_prefix;
	$link = mysql_connect($db_host, $db_user, $db_pass);
	$db = mysql_select_db($db_name);
	$this->prefix = $db_prefix;
	return $link;
}

Step 4: Add legacy support for PHP4

PHP 4 handles constructors differently. You must create a function with the name of your class within your class. Here, I must make the function icdb().

function icdb() {
	$this->__construct();
}

Final Code

You're now done! Here's all of the code put together.

class icdb {
	function icdb() {
		$this->__construct();
	}

	function __construct($db_host, $db_user, $db_pass, $db_name) {
		global $db_prefix;
		$link = mysql_connect($db_host, $db_user, $db_pass);
		$db = mysql_select_db($db_name);
		$this->prefix = $db_prefix;
		return $link;
	}
}

And to initialize the class:

$icdb = new icdb("localhost", "myUser", "myPass", "myDb");

And that's it! You are now connected to a database. Now all you need is to add functions to the class to work with the database!

You can use this method to add parameters to any PHP class.

This is my first tutorial, so please tell me if it doesn't make sense. :p