Organize and relate class in PHP -

well, trying adapt old code more object oriented model find difficulties in doing it. structure of classes this:

// config.php class config {     const setting1 = 'value';     const setting2 = 'value'; }  // main.php include 'config.php'  class main {     var $config;     var $info;     var $db;      function _construct() {         $this->config = &new config;         $this->info = &new info;         $this->db = &new db($this);     } }  class info {     function getsetting($a, $config) {         if ($a>0) return $config::setting1;         return $config::setting2;     } }  class db {     function _construct($main) {         $setting1 = $main->config::setting1;     } }  // index.php $main = new main; echo $main->info->getsetting(1, $main->config); 

so, see, there incorrect things in code. want have inside main class, create $main object , there access other object. db need constant config yet don't want create new config inside db use 1 main. same happens info.

the problem should fixed this:

// config.php class config {     public static $setting1 = 'value';     public static $setting2 = 'value'; }  // main.php include('config.php');  class main {     private $info = null;     private $db = null;      public function _construct() {         $this->info = new info();         $this->db = new db();     }      public function getsetting($a) {         return $this->info->getsetting($a);     } }  class info {     public function getsetting($a) {         if ($a>0) return config::$setting1;         return config::$setting2;     } }  class db {     public function _construct() {         $setting1 = config::$setting1;     } }  // index.php $main = new main(); echo $main->getsetting(1);