reference.php

<?php
class Hoge {
    private $h;
    public function __construct(&$h) {
        $this->h &= $h;
    }

    public function hhh($str) {
        $this->h["str"] = $str;
    }
}

$k = array("str" => "string!!");
$hoge = new Hoge($k);
print_r($k);
$hoge->hhh("changed");
print_r($k);


//Array
//(
//    [str] => string!!
//)
//Array
//(
//    [str] => changed
//)