Re: Rounding with decimal types

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 26 Nov 2007 08:15:02 +0000 (UTC), Wiktor Moskwa wrote:

> I'd like to know if there is "round up" and "unbiased rounding"
> implemented for decimal types in Ada and if not, how "is it usually done"?

Yep, this is a problem, I faced it too but for floating-point numbers when
implemented interval computations. There one needs rounding up and down as
well.

I would suggest something as clumsy as:

   -- Up-rounding multiplication
function "*" (Left, Right : My_Decimal) return My_Decimal is
   type Impl is new My_Decimal;
begin
   if Left = 0.0 then
      return 0.0;
   else
      declare
         Result : Impl := Impl'(Impl (Left) * Impl (Right));
      begin
         if Result / Left /= Right then
            return My_Decimal'Succ (My_Decimal (Result));
         else
            return My_Decimal (Result);
         end if;
      end;
   end if;
end "*";

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de