How to use keyword "static" to make this work as intended?

Question

I am preparing for the ZEND Certified Engineer-Exam. Using the TestPassport-Engine "Virtual Exam", I came across this question:

Consider the following code. Which keyword should be used in line marked in bold to make this code work as intended?

abstract class Base {
    protected function __construct() {}

    public function create(){   
        // this line
        return new self();
    }

    abstract function action();
}

class Item extends Base {
    public function action () { echo __CLASS__; }
}

$item = Item::create();
$item->action();

And the correct answer is static. So, how should that look like in the end?

With the answer given, a little investigation of the keyword `static` should tell you where to put it.. It is really easier to spend two minutes on php.net than to type this whole question, especially if you are trying to learn PHP. I mean, the static method call is already there in the code. — GolezTrol, Jul 16 '13 at 12:08
The fact that you are having to ask this question on StackOverflow just reinforces my personal belief that certifications like these are ultimately useless. "Certified Engineer" ... — crush, Jul 16 '13 at 12:11
@crush - you hit the nail on the head, have my upvote! I couldn't agree more. — N.B., Jul 16 '13 at 12:12
@crush You can also say he is not ready for the exam. If someone ask a question like this does not mean the certification is useless. — Perry, Jul 16 '13 at 12:23
Well, what can I say? Still learning - thanks for your encouragement. — MBaas, Jul 16 '13 at 12:31
@Perry 1. Memorize answer to all exam questions. 2. ??? 3. Profit — crush, Jul 16 '13 at 12:35
It's not a big secret that zend "certification" exists so that anyone can get a certificate for not-so-much money. It's also nice pocket money for Zend as well. No offense meant, but there are many Zend Certified people on SO who are spouting total nonsense all the time. It's cool for learning though. Good luck Baas and I hope you don't end up being one of the "bad" certified ones. — N.B., Jul 16 '13 at 13:06

score 2 · Accepted Answer · answered Jul 16 '13 at 12:10

2

Simply change

public function create() {
    return new self();
}

to

public static function create() {
    return new static();
}

See here.

answered Jul 16 '13 at 12:10

n3rd

5,989
4
39
56

This is the correct answer, mine was wrong, I have deleted it. – Hein Andre Grønnestad Jul 16 '13 at 12:16
The question calls for changes on *one* line though... – phant0m Jul 16 '13 at 12:20
1

Besides the manual: Here's also a short explanation of the difference between `new static()` and `new self()`: [New self vs. new static](http://stackoverflow.com/a/5197655/1456376). – insertusernamehere Jul 16 '13 at 12:22

How to use keyword "static" to make this work as intended?

1 Answers1