[SOLVED] [Beginner] Cannot access empty property

[AV]

Hi all,

I started to learning OOP and just on start I got an error:

Fatal error: Cannot access empty property in (...)books.php on line 16

The php code:

class Books{

var $cena;
var $tytul;

function setCena($par) {
echo $this->$cena = $par;
}

function getCena(){
echo $this->$cena.'<br />';
}

function setTytul($par){
echo $this->$tytul = $par;
}

function getTytul(){
echo $this->$tytul.'<br />';
}
}

$fizyka = new Books;
$chemia = new Books;
$matematyka = new Books;

$fizyka->setTytul("Fizyka dla kazdego - cz. I");
$fizyka->setCena("40zl");

$chemia->setTytul("Chemia wokol nas");
$chemia->setCena("30zl");

$matematyka->setTytul("Pitagoras i ja");
$matematyka->setTytul("35zl");

//WYSWIETLAMY KSIAZKI
$fizyka->getTytul(); echo"||"; $fizyka->getCena();

Tytul=title, Cena=price

 

What do I do wrong?

[coder_]

function setCena($par) {
echo $this->cena = $par;
}

 

Change your functions to look like this. You don't use "$" when you are pointing to some object.

[emehrkay]

coder_ is correct. when you reference a class member, "$this->" replaces the $

 

Also your methods get and set are kinda unnecessary (in their current state) as you can access those members because they are public

 

$b = new Books();

$b->cena = 'some cena'; //this is the same as your setCena() method

 

 

And if at all possible, I'd say learn PHP OOP through PHP5

[AV]

Thank you very much guys!

 

Do you have any clearly written tutorials for OOP in PHP5?

[coder_]

Her you can learn a lot:

 

http://www.php.net/manual/en/language.oop5.php

 

 

 

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