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Sender: "Team Ada: Ada Advocacy Issues (83 & 95)" <[log in to unmask]>
From: Chris Sparks <[log in to unmask]>
Date: Wed, 21 Jun 2000 06:39:22 -0700
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Reply-To: Chris Sparks <[log in to unmask]>
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Stanley Allen wrote:

> How about an open-source GUI financial caculator written in Ada,
> making use of decimal-digits fixed-point arithmetic and picture strings?

A financial calculator may be nice, however, this kind of application has
been done and redone so many times.  I am not saying that we couldn't
develop a slick calculator, give it for free (excuse me Bob (Leif) for I have
sinned! :-), in hopes to generate interest in Ada products by the community.

> I've been looking at some of the free (libre) Linux fin calcs and they
> seem to be using double (or worse, float) for all real calculations.
> I've been led to believe by some comments in this forum that floating-point
> is a poor choice for financial work.

Float is not accurate.  Fixed is better, however, decimal arithmetic is much
better for financial calculations.

> Could it be done better in Ada?  What advantages could be claimed for

Of course!  Anything is better when done in Ada! :-)   Well at least by the
folks in this group at least! :-)

> such a calculator?  Are there some current popular applications in

Advantages could be the correctness factor, maybe ease of use, appeal to
the masses who aren't CPAs or accountants.

> this category to emulate?

I don't know of any other calculators except Micro$oft's, Unix calculators,
and the ones on Linux.

> This train of thought occurred to me as I was making use of the MS Windows
> calculator.  I was wondering if the Linux world had stabilized on a common
> desktop calculator yet, and if not perhaps an Ada implementation would be
> appropriate & attractive.  The MS Windows calculator has a 'standard' view
> and a 'scientific' view.  Perhaps a GTK+ based calculator for Linux which
> mimicked the MS Windows one and added an extra 'financial' view could
> become popular.

A GTK based calculator is the way to go since you should be thinking of
porting it to both Windows and Linux.

All of this discussions reminds me of an idea that I have been thinking of
for some time now.  I normally keep track of all of my finances via excel
spread sheets.  The one major draw back I have with the product, and it
could be from my lack of understanding the tool, is that links to other pages
can get really screwed up when I start moving stuff around.  I would like to
see a product deal with my financial transactions as objects that can be
linked to other objects.  Free to move about.

I would like to see a purchase which is linked to my credit card payment
which is then linked to my banking account.  This way I can keep
full track of all transactions, where they were paid from, and build reports
showing where my money is going.  All of this with a simple interface and
easy to use database and viola!  You've made me happy in not having to
use excel anymore.  Using decimal arithmetic is a great idea.  With excel
using double float I don't get the exactness that I need.  I especially note
when I use a formula to half an amount and display it to two decimal
places.  I notice a lot of error (penny wise) when I start summing totals
which really irks me.  Forces me to hard code values instead of formulas.

Chris Sparks, Boeing
(714) 372 - 9791