Programming Forums > Web Development and Design > PHP

dark_omen · Jul 12th, 2006, 3:26 PM

I made a php class, but how do I use it?
I know that you make an object using the constructor:

$obj = new ClassName();

And I know that you can use functions of the class by:

(Toggle Plain Text)

$obj->myMethod();

but for some reason it gives me an error. Is there something I am missing (btw all I did was make the object in the other php file)?

Any help would be great, as well as a good tutorial on classes in PHP.
Thanks

tempest · Jul 12th, 2006, 3:29 PM

1. We need to see your source to pin point your problem, that pseudo code doesn't tell us much.
2. What version of PHP?

dark_omen · Jul 12th, 2006, 3:41 PM

Well here it is, but it's not much different from what I posted before.
[php]
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Test</title>
</head>
<?php
$obj = new myClass();
echo $obj->write();
?>
<body>
</body>
</html>
[/php]

And this is the class:
[php]
<?php
class myClass{
var $h;

//constructor
function myClass(){
$h = "Hello";
}

function write(){
return $h;
}
}
?>
[/php]

And I am writing it in php 5.1.4

Jimbo · Jul 12th, 2006, 3:52 PM

Try using include_once() or require_once() to put your class definition in the file where it's being used.

(Toggle Plain Text)

<?php
   include_once("myclass.php"); // or whatever
   $obj = new MyClass;
   $obj->write();
?>

grimpirate · Jul 12th, 2006, 5:22 PM

Your class should be as follows dark_omen:

(Toggle Plain Text)

<?php
class myClass{
    var $h;

    //constructor
    function __construct(){
        $this->$h = "Hello";
    }
    
    function write(){
        return $this->$h;
    }
}
?>

So basically for any instance field of the class or when you want to return a value which uses an instance field in its computations, you have to specify $this-> in your code. Also, your constructor for the class is always named __construct. And that should make your class work as you want it to.

Jimbo · Jul 12th, 2006, 5:36 PM

Quote:

Originally Posted by grimpirate

Also, your constructor for the class is always named __construct. And that should make your class work as you want it to.

Pre-PHP 5, it was the same name as the class, and it should be backwards compatible. But, as this is being done in PHP >= 5, __construct is correct.

DaWei · Jul 12th, 2006, 6:20 PM

$this->$h should be $this->h. I believe his biggest problem was not having the class definition available in the file where he used it.

grimpirate · Jul 12th, 2006, 7:55 PM

Good looking out DaWei, I accidentally left that dollar sign in there. Here is the properly revised code.

(Toggle Plain Text)

<?php
class myClass{
    var $h;

    //constructor
    function __construct(){
        $this->h = "Hello";
    }
    
    function write(){
        return $this->h;
    }
}
?>

dark_omen · Jul 12th, 2006, 8:58 PM

thanks for the info

Jul 12th, 2006, 3:26 PM	#1
dark_omen Hobbyist Programmer Join Date: Dec 2004 Posts: 125 Rep Power: 4	PHP class I made a php class, but how do I use it? I know that you make an object using the constructor: (Toggle Plain Text) $obj = new ClassName(); $obj = new ClassName(); And I know that you can use functions of the class by: (Toggle Plain Text) $obj->myMethod(); $obj->myMethod(); but for some reason it gives me an error. Is there something I am missing (btw all I did was make the object in the other php file)? Any help would be great, as well as a good tutorial on classes in PHP. Thanks

Jul 12th, 2006, 3:29 PM	#2
tempest Programming Guru Join Date: Oct 2004 Posts: 1,041 Rep Power: 5	1. We need to see your source to pin point your problem, that pseudo code doesn't tell us much. 2. What version of PHP? __________________

Jul 12th, 2006, 3:52 PM	#4
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 763 Rep Power: 3	Try using include_once() or require_once() to put your class definition in the file where it's being used. (Toggle Plain Text) <?php include_once("myclass.php"); // or whatever $obj = new MyClass; $obj->write(); ?> <?php include_once("myclass.php"); // or whatever $obj = new MyClass; $obj->write(); ?>

Jul 12th, 2006, 5:22 PM	#5
grimpirate King of Portal Join Date: Sep 2005 Posts: 431 Rep Power: 4	Your class should be as follows dark_omen: (Toggle Plain Text) <?php class myClass{ var $h; //constructor function __construct(){ $this->$h = "Hello"; } function write(){ return $this->$h; } } ?> <?php class myClass{ var $h; //constructor function __construct(){ $this->$h = "Hello"; } function write(){ return $this->$h; } } ?> So basically for any instance field of the class or when you want to return a value which uses an instance field in its computations, you have to specify $this-> in your code. Also, your constructor for the class is always named __construct. And that should make your class work as you want it to. __________________ Lo, there do I see my father. 'Lo, there do I see My mother, and my sisters, and my brothers. 'Lo, there do I see The line of my people... Back to the beginning. 'Lo, they do call to me. They bid me take my place among them. In the halls of Valhalla... Where the brave... May live... ...forever.. GrimBB \| Mimesis

Jul 12th, 2006, 6:20 PM	#7
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	$this->$h should be $this->h. I believe his biggest problem was not having the class definition available in the file where he used it. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jul 12th, 2006, 3:41 PM	#3
dark_omen Hobbyist Programmer Join Date: Dec 2004 Posts: 125 Rep Power: 4	Well here it is, but it's not much different from what I posted before. [php] <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Test</title> </head> <?php $obj = new myClass(); echo $obj->write(); ?> <body> </body> </html> [/php] And this is the class: [php] <?php class myClass{ var $h; //constructor function myClass(){ $h = "Hello"; } function write(){ return $h; } } ?> [/php] And I am writing it in php 5.1.4

Jul 12th, 2006, 7:55 PM	#8
grimpirate King of Portal Join Date: Sep 2005 Posts: 431 Rep Power: 4	Good looking out DaWei, I accidentally left that dollar sign in there. Here is the properly revised code. (Toggle Plain Text) <?php class myClass{ var $h; //constructor function __construct(){ *$this->h* = "Hello"; } function write(){ return *$this->h*; } } ?> <?php class myClass{ var $h; //constructor function __construct(){ $this->h = "Hello"; } function write(){ return $this->h; } } ?> __________________ Lo, there do I see my father. 'Lo, there do I see My mother, and my sisters, and my brothers. 'Lo, there do I see The line of my people... Back to the beginning. 'Lo, they do call to me. They bid me take my place among them. In the halls of Valhalla... Where the brave... May live... ...forever.. GrimBB \| Mimesis

Jul 12th, 2006, 8:58 PM	#9
dark_omen Hobbyist Programmer Join Date: Dec 2004 Posts: 125 Rep Power: 4	thanks for the info

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Programming Forums > Web Development and Design > PHP

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