Re: What about big integers in Ada 2005?

[Robert A Duff <bobduff@shell01.TheWorld.com>]

clubley@remove_me.eisner.decus.org-Earth.UFP (Simon Clubley) writes:

> In article <1x4pe4pv41qsn$.m5c5jawjqcpq.dlg@40tude.net>, "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> > 
> > Curious, why somebody would like to use BCD for 45!? I cannot imagine any
> > use of BCD except than to speed up conversions to ASCII, which is not an
> > issue in these days.
> 
> One reason to use BCD is because it's a compact data representation.

Heh?  Binary is more compact that BCD.

I think the only reason to use BCD these days (instead of binary) is to
interface to something that uses BCD.  In the old days, another reason
was to avoid the cost of converting strings to binary integers and
vice-versa, but that seems like an obsolete reason at this 

Am I right?

> One real world use of BCD that I have come across is in SMS messages where 
> it is used to encode all the SMS message centre/destination/originating
> telephone numbers in the SMS TPDU packets. (Details in SMS specification
> GSM 03.40).

But one does not normally do arithmetic on telephone numbers,
so considering them "numbers" is questionable.  You could do
it this way:

    type Digit is ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9');
    type Phone_Number is array (...) of Digit;
    for Phone_Number'Component_Size use 4;

- Bob