Question

Hi stackOverflow Family :),

I have a question, and I didt find the answer elsewhere. I try to explain my problem:
I have a class, and if I create an other class from it, from that child class I couldnt access the parent’s properties.
I did something wrong?
I tried to copy my class variable to a local and try to give back that local one, but neither works of the following 3 way.

Here is my examples.
At first I simple create an object:

$test = new test();

And my two class is the following:

class test {

    public $testvar;

    public function __construct() {
        $this->testvar = 1234568;
        echo ":) ".$this->testvar();
        $test2 = new test2();
}

    public function testvar() {
        echo "testvar() called > ";
        return $this->testvar;
    }
}

And test2:

class test2 extends test  {

    public function __construct() {
        echo "<br>:| this-> ".$this->testvar;
        echo "<br>:| parent:: ". parent::testvar();
        echo "<br>:| "; $this->testvar();
    }

}

May somebody have an idea?
Thx

Answer 1

You’ve misunderstood the inheritance concept. Instantiating test2 in the constructor function of test is not inheritance.

The constructor of test was not called, therefore testvar was not set. Remove $test2 = new test2(); from the constructor of test. Try:

class test {

    public $testvar;

    public function __construct() {
        $this->testvar = 1234568;
        echo ":) ".$this->testvar();
}

    public function testvar() {
        echo "testvar() called > ";
        return $this->testvar;
    }
}

class test2 extends test  {

    public function __construct() {
        parent::__construct();
        echo "<br>:| this-> ".$this->testvar;
        echo "<br>:| "; $this->testvar();
    }

}

$test2 = new test2();

See also the PHP manual on constructors (and classes too).