transfer variables between class A and B - php

Question

How i can run method $this->ob->getVar() inside class B function C here ? I get no. Did i must transfer string to constructor ?
<?php
class A{
public $tabb = array('1'=>'one', '2'=>'two');
public $index;
public function setVar($v){
$this->index = $v;
}
public function getVar(){
return $this->index;
}
public function arr(){
return $this->tabb;
}
}
class B{
public $tab;
public function __construct($var){
$this->ob=new A;
$this->tab = $var;
}
public function C(){
return $this->D($this->tab, $this->ob->getVar());
}
public function D($l, $j){
if(is_array($l) && isset($j)){
print 'yes';
} else {
print 'no';
}
}
}
$obb = new A;
$obb->setVar('onetwo');
$k = $obb->arr();
$obbb = new B($k);
$obbb->C();
?>

Answer 1

First, for the sake of convention your B class should declare a private variable of $obj, but that is not necessary in PHP.
Second, your B class is just creating a new instance of A in its constructor. So you have two different A classes. The once inside B never has its index property populated.
If you wanted to have the A object created outside the B object you'll have to pass it in like this:
$obbb = new B($k, $obb);
So now your new B constructor is something like this:
public function __construct($var, $someObject){
if (!empty($someObject)) {
$this->ob = $someObject;
}
else {
$this->ob=new A;
}
$this->tab = $var;
}