class User
    {
        public $db;
        public $id;
        public $username;
        public $password;

        public function __construct($db, $id = 0)
        {
            $this->db = $db;
            $this->id = $id;
        }

        public function showOne()
        {
            if($this->$id !== 0)
            {
                $query = mysql_query("SELECT `username`, `password` FROM `user` WHERE `id` = $this->id");
                $result = mysql_fetch_assoc($query);

                    if($result)
                    {

                        $this->username = $result['username'];
                        $this->password = $result['password'];
                    }

            }
        }