Problem with object variable

[ecoffin]

I've been working on this problem for hours now, and I can't tell if I'm just losing my mind or there is actually a php issue here.
I am using PHP v.4.3.3

I have an object variable is being mysteriously set to 0 from an null state after we switch to another function.

Here is the code that calls my object:
$question = new Question();
$question->set_response(null);

Here is the object:

class Question {

var $response;

function set_response($response=null) {
$this->response = $response;
print "In set_response: {$this->response}<br>";
$this->save();

return $this->response; 

} // End function set_response

function save() {
print "In save: {$this->response}<br>";
} // end function save()

} // end class Question

And here is the output:
In set_response:
In save: 0

If anyone can help me, that'd be great. I'm ripping my hair out here.

Thanks,
Erica

[planetsim]

Basically it is outputting correctly. Try putting 2 as the function argument. You should see a different result.