class Database {
    public $conn;
    protected $hostname;
    protected $username;
    protected $password;
    protected $dbname;

    public function __construct ( $hostname, $username, $password, $dbname ) {
        global $conn;
        $this->conn = $conn;
        $this->hostname = $hostname;
        $this->username = $username;
        $this->password = $password;
        $this->dbname = $dbname;

        $conn = new mysqli($hostname, $username, $password, $dbname) or die(('Could not connect to this hostname.' .$hostname. 'Error: ' . mysqli_connect_error() . $conn->connect_error);

        if ($conn == false) {
            trigger_error('Error connecting: ' . mysqli_connect_error() . $conn->error . $conn->errno, E_USER_ERROR);
            exit;
        }
        $conn->set_charset('utf8');
    }
}

// creating the object of connection.
$db = new Database ( 'localhost', 'root', '', 'table_name' );

// debug
print '<pre>';
print_r($db);
print '</pre>';

print '<pre>';
var_dump($db);
print '</pre>';

print '<hr>';
print '<pre>';
print_r($conn);
print '</pre>';

print '<pre>';
var_dump($conn);
print '</pre>';

print '<hr>';
printf("<pre>%s</pre>",print_r($conn, true));