PHP Classes

[erotic sock]

This is sort of tied in with the question I asked earlier. Let me know
if I'm going insane, because I could swear classes are supposed to work
this way in other languages.

Let's say we have class Counter. It's declared like this.

class Counter
{
var $counter = 0;

function count()
{
$this->counter++;
}
}

//and class Test

class Test
{
function tester($counter ) // receives counter object
{
$counter->count();
}
}

//Now, let's say in the main part of the program it works like this:

$counter = new Counter();
$test = new Test();

echo $counter->counter; // should echo 0, does print out 0
$test->tester($counte r);
echo $counter->counter; // should echo 1, actually prints out 0


Why doesn't this work? I'm sure it works in C#. If this is the way it's
supposed to work in PHP, I believe it's fairly silly. Is there a way to
hack it into working? I suppose I could use globals, but I'd really
rather not. Does PHP5 change this?

Thanks

~ sock

[Chris Hope]

Re: PHP Classes

erotic sock wrote:
[color=blue]
> This is sort of tied in with the question I asked earlier. Let me know
> if I'm going insane, because I could swear classes are supposed to work
> this way in other languages.
>
> Let's say we have class Counter. It's declared like this.
>
> class Counter
> {
> var $counter = 0;
>
> function count()
> {
> $this->counter++;
> }
> }
>
> //and class Test
>
> class Test
> {
> function tester($counter ) // receives counter object
> {
> $counter->count();
> }
> }
>
> //Now, let's say in the main part of the program it works like this:
>
> $counter = new Counter();
> $test = new Test();
>
> echo $counter->counter; // should echo 0, does print out 0
> $test->tester($counte r);
> echo $counter->counter; // should echo 1, actually prints out 0
>
>
> Why doesn't this work? I'm sure it works in C#. If this is the way it's
> supposed to work in PHP, I believe it's fairly silly. Is there a way to
> hack it into working? I suppose I could use globals, but I'd really
> rather not. Does PHP5 change this?[/color]

If I recall correctly, PHP4 (and earlier) pass objects by value and PHP5
passes objects by reference. So in the 'Test' class you are modifying the
property of a passed in value, and not the original value. To make it do
what you are expecting you need to explicitly pass in the object in by
reference by either putting an & in front of the variable like so:

function tester(&$counte r)
{
$counter->count();
}

or else when you call the function like so:

$test->tester(&$count er);

--
Chris Hope
The Electric Toolbox - http://www.electrictoolbox.com/

[erotic sock]

Re: PHP Classes

Chris Hope wrote:[color=blue]
> erotic sock wrote:[color=green]
>><snip my question>[/color]
>
> If I recall correctly, PHP4 (and earlier) pass objects by value and PHP5
> passes objects by reference. So in the 'Test' class you are modifying the
> property of a passed in value, and not the original value. To make it do
> what you are expecting you need to explicitly pass in the object in by
> reference by either putting an & in front of the variable like so:
>
> function tester(&$counte r)
> {
> $counter->count();
> }
>
> or else when you call the function like so:
>
> $test->tester(&$count er);
>[/color]

Thanks for that. I didn't realise the & modifier worked.

~ sock