Question

I’m getting sort of an unexpected behaviour while trying to implement a class A that uses a class B. Here are the contents of the files:

> cat test.php
<?php

error_reporting(E_ALL);
require_once("A.php");
//require_once("B.php"); //now it'd work, but it's not the point

$a = new A();
$b = $a->getB();
var_dump($b);
$b->sayHi();
> cat A.php
<?php

require_once('B.php');

class A
{
        private $b;

        public function getB()
        {
                return $this->b;
        }

        public function __construct()
        {
                $b = new B();
        }
}
> cat B.php
<?php

class B
{
        public function sayHi()
        {
                echo "Hi!";
        }
}
> php test.php
NULL
PHP Fatal error:  Call to a member function sayHi() on a non-object in /var/www/przypadek_testowy/test.php on line 10

Is there some PHP quirk I should have known about? Requiring B.php in test.php is ugly in this case and I’d prefer a better solution.

Answer 1

Replace $b = new B(); with: $this->b = new B(); in your A class.

See also that require_once is a statement, not a function. So you can use it without quotes.