Using Class Attributes ?

[gdaily]

Hi All,

I just picked up PHP& MySQL Web Development by Luke Welling and Laura Thomson 3rd edition and am having problems with the examples they use under 'Using Class Attributes'. Specifically, they say that "If an attribute of your current class is called $attribute, you refer to it as $this->attribute ..." What I don't understand is, in some of the examples the attribute has the $ and some it doesn't. I'm assuming that there is a reason for this, and that it's not merely a typo. Anyone ? Thanks, in advance.

[toplay]

I don't know the book. My guess it's a typo. Maybe you can write out here what's exactly in the book. But, the use of $this must always have a dollar sign in front of it. It's the way you access variables from within a class for example.

class demo {

var $msg;

function demo() {
     $this->msg = 'Hello World!';
}

function display_msg () {
    echo $this->msg;
}

}

$a_demo = new demo();
$a_demo->display_msg();  // outputs:  Hello World!

demo::display_msg(); //<-- not allowed since method uses $this

[gdaily]

Thanks for the reply, here's the first example:

class classname
{
var $attribute;
function operation($param)
{
$this->attribute =$param
echo $this->attribute;
}
}

this closely resembles your example and makes sense, but then they used this example (perhaps my confusion is here because the get and set are handled differently?)

class classname
{
var $attribute;
function__get($name)
{
return $this->$name; // why is it $this->$name instead of $this->name ?
}
}

Thanks.

[toplay]

The $name is being passed as an argument and will contain the name of the variable. So, if "attribute" is passed, then this:

$this->$name

ends up being:

$this->attribute

.

[gdaily]

Ok, cool. Thanks again!