Question

if i have a class that has a index function and i extend it and create another index function. Will the index function in the extension overwrite the parents index function? also, what is parent::__construct() exactly doing in the second class in a construct?

class someclass
{
    public function index()
    {
        //do something
    }
}

class newclass extends someclass
{
    function __construct()
    {
        parent::__construct();
    }

    public function index()
    {
        //do something
    }
}

Answer 1

You can just do some simple test

echo "<pre>";
$b = new B();
$b->index();

echo PHP_EOL;

$c = new C();
$c->index();

Output

A.A::__construct
B.B::index <-------------- Parent index overwrite 

A.A::__construct   <------ Still calls it anyway
A.A::index         <------ Calls A:index
C.C::index         <------ Calls B:index 

Classes

class A {

    function __construct() {
        echo __CLASS__, ".", __METHOD__, PHP_EOL;
    }

    public function index() {
        echo __CLASS__, ".", __METHOD__, PHP_EOL;
    }
}
class B extends A {

    function __construct() {
        parent::__construct();
    }

    public function index() {
        echo __CLASS__, ".", __METHOD__, PHP_EOL;
    }
}
class C extends A {

    public function index() {
        parent::index();
        echo __CLASS__, ".", __METHOD__, PHP_EOL;
    }
}