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Groups > comp.lang.c > #164261

Re: Can this program be improved?

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Can this program be improved?
Date 2022-01-04 09:31 +0100
Organization A noiseless patient Spider
Message-ID <sr10lv$i2t$1@dont-email.me> (permalink)
References (18 earlier) <f96e4ea3-3c52-4869-99c6-c0806621b40cn@googlegroups.com> <8735m41lwy.fsf@nosuchdomain.example.com> <b2918a53-acd6-4c46-9b58-6ac578bc055cn@googlegroups.com> <87y23wz9l9.fsf@nosuchdomain.example.com> <ff338dd2-a4fe-4b06-8b4a-e3622b666c9en@googlegroups.com>

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On 04/01/2022 00:43, Malcolm McLean wrote:
> On Monday, 3 January 2022 at 23:24:46 UTC, Keith Thompson wrote:
>> Malcolm McLean <malcolm.ar...@gmail.com> writes: 
>>> On Monday, 3 January 2022 at 22:42:32 UTC, Keith Thompson wrote: 
>>>> Malcolm McLean <malcolm.ar...@gmail.com> writes: 
>>>>> On Monday, 3 January 2022 at 04:49:56 UTC, Keith Thompson wrote: 
>>>> [...] 
>>>>>> I won't discuss politics here. 
>>>>>>
>>>>> When hamburgers [more politics] 
>>>>
>>>> Malcolm, knock it off. 
>>>>
>>> Don't you see that that if you are discussing the representation of monetary 
>>> values, there are a few obvious things to consider? Whether they are real or 
>>> discrete is one. Another is range. What's the maximum value that we might 
>>> need to represent?
>> Of course I see that. And if you want to talk about how hyperinflation 
>> and/or extremely large quantities might affect financial calculations. 
>> If you assume an upper bound on a quantity, it's best to make that 
>> assumption explicit. 
>>
> Maybe not. If we assume that a hamburger costs about a dollar in today's money,
> in Weimar Germany the mark got up to 4 trillion to the dollar before being
> abandoned. So clearly we need to plan for a burger costing at least 4 trillion
> dollars. But how high could it go? Very hard to answer. But a double will handle
> values of up to 10^308. It's hard to see even hyperinflation getting that high
> before the monetary system totally collapses. So we're probably safe as far
> as range is concerned with a double.
> A double also has 53 bits of precision. that allows values of up to about 10^16
> to be represented exactly. That's 10^14 is we store values in cents.  So is that
> enough? That's a much harder call. If you are dealing with hamburger joints,
> then you can have quite a bit of inflation before you fail to be able to represent
> as many hamburgers as you could reasonably sell. Then you start dropping
> cents. But by the time you start dropping cents, the cent will be a notional unit
> of currency. All the coins will have been melted down for metal. So is 53 bits
> enough? I don't write programs that deal withh amounts of money, so I don't
> really know. 
> However if I had to choose a C type, I'd probably go for integer representation
> of amounts in cents, using a double.

If you are writing a simple example or test program, use whatever type
suits.  If you are writing a single-purpose or single-user program, use
whatever type suits.  These would be integer types if you want to store
integer cents (or pennies, or whatever), or doubles if you want to make
it easy to do interest rate calculations.  This will be fine to tell you
the values involved - and the real legal tracking of money will be done
by banks and accountants using software that follows the required rules.

If you are writing a serious program, you find the rules for the
jurisdictions that are relevant.  You don't make guesses based on vague
memories of school-time history classes or think "cents is good enough".
 In some places, the rules involved are much more demanding - I know
that for some currencies, you need to track six digits after the decimal
point.

>>
>> It's your assertions that specific currently proposed policies will lead 
>> to hyperinflation that are off-topic and annoying.
>>
> As far as C programmers are concerned, the question is, is hyperinflation
> something that happened in Weimar Germany back in the olden days,
> and could never happen in the modern US. Or is it a real and present
> danger. Is this something we should be thinking about?
> 

No, it is not something you need to think about as a C programmer.  You
write the code you need - and for an example program like the OP's, it
doesn't need any connection to reality.  On the other hand, if you want
to write serious financial software, you follow the rules required - you
don't invent them.

> If you ask some qualified people, I think you'll find that they are extremely
> worried.
> 

Could modern economies spiral into hyperinflation?  Of course it is
possible.  We've seen it before, worse and more recently than the Weimar
Republic.  If you want to learn about and discuss this, find an
appropriate place to do so rather than mixing limited historical points
with paranoid conspiracy theories in a programming group.  Or perhaps
find a qualified person and ask them, to put your mind at ease.  Just be
sure to look for that qualified person in an appropriate place - not
comp.lang.c, and not some Facebook post by your Auntie's neighbour's
friend whose dad is a janitor in a bank so he should know.

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Thread

Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-25 01:00 +0000
  Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-24 21:44 -0800
    Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2021-12-25 12:56 +0100
    Re: Can this program be improved? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-25 11:13 -0800
    Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-25 23:50 +0100
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 18:52 +0000
      Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-26 19:22 +0000
        Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 21:30 +0000
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-26 22:02 +0000
          Re: Can this program be improved? Richard Damon <Richard@Damon-Family.org> - 2021-12-26 18:24 -0500
          Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-27 00:47 +0000
    Re: Can this program be improved? Guillaume <message@bottle.org> - 2021-12-29 17:52 +0100
      Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-29 17:49 +0000
        Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-29 11:33 -0800
          Re: Can this program be improved? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-12-29 22:45 -0500
            Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-30 00:35 -0800
              Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2021-12-30 10:19 +0100
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 18:19 +0000
            Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 19:33 +0000
        Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 14:37 -0800
          Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-29 23:09 +0000
            Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2021-12-29 23:54 +0000
              Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 16:11 -0800
              Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:34 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-30 12:49 +0000
                Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 21:04 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 02:13 +0000
            Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 16:09 -0800
              Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:59 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-29 17:48 -0800
                Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 20:47 +0000
              Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-30 01:06 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-30 04:48 -0800
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-30 18:16 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 02:20 +0000
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2021-12-31 18:25 +0100
                Re: Can this program be improved? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-12-31 18:13 -0500
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-31 23:59 +0000
                Re: Can this program be improved? "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-12-31 16:20 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-31 16:35 -0800
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 00:53 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-31 20:22 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-31 22:04 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-01 14:59 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-02 17:22 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-02 20:49 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 03:09 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-03 16:22 +0000
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-03 14:42 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 14:52 -0800
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 22:58 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 04:27 -0800
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 13:39 +0000
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 00:18 +0100
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-03 15:24 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 15:43 -0800
                Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2022-01-03 21:19 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-04 09:23 +0100
                Re: Can this program be improved? Guillaume <message@bottle.org> - 2022-01-04 18:18 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 10:35 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-04 14:07 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 15:11 -0800
                Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-01-04 15:47 -0800
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 18:30 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 23:46 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-04 18:41 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 10:52 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 19:00 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 11:15 -0800
                Re: Can this program be improved? Guillaume <message@bottle.org> - 2022-01-04 21:57 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-04 21:02 +0000
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-04 21:38 +0000
                Re: Can this program be improved? Manfred <noname@add.invalid> - 2022-01-04 23:01 +0100
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 09:31 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 01:30 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 14:55 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-04 06:21 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-04 16:49 +0100
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 15:56 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-04 15:03 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 22:54 +0000
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 09:22 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 03:30 -0800
                Re: Can this program be improved? David Brown <david.brown@hesbynett.no> - 2022-01-03 17:22 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 08:48 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 18:42 +0100
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-03 17:59 +0000
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 11:09 -0800
                Re: Can this program be improved? Mateusz Viste <mateusz@xyz.invalid> - 2022-01-03 20:32 +0100
                Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-01-03 11:58 -0800
                Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2022-01-03 18:13 +0000
                Re: Can this program be improved? gazelle@shell.xmission.com (Kenny McCormack) - 2022-01-03 20:05 +0000
                Re: Can this program be improved? Bart <bc@freeuk.com> - 2022-01-01 16:53 +0000
          Re: Can this program be improved? Kaz Kylheku <480-992-1380@kylheku.com> - 2021-12-30 00:29 +0000
  Re: Can this program be improved? Bart <bc@freeuk.com> - 2021-12-25 12:47 +0000
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 18:56 +0000
  Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 17:38 +0000
    Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2021-12-25 10:58 -0800
      Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 19:16 +0000
        Re: Can this program be improved? Öö Tiib <ootiib@hot.ee> - 2021-12-25 11:25 -0800
      Re: Can this program be improved? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-25 15:01 -0800
        Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-25 23:09 +0000
          Re: Can this program be improved? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-25 20:56 -0800
    Re: Can this program be improved? scott@slp53.sl.home (Scott Lurndal) - 2021-12-25 19:30 +0000
      Re: Can this program be improved? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-12-25 15:50 -0800
        Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:02 +0000
    Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-25 11:53 -0800
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:00 +0000
  Re: Can this program be improved? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-12-25 11:22 -0800
    Re: Can this program be improved? Manu Raju <MR@invalid.invalid> - 2021-12-26 19:01 +0000
  Re: Can this program be improved? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-12-25 13:27 -0800
    Re: Can this program be improved? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2021-12-25 16:06 -0800
  Re: Can this program be improved? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-12-29 15:21 +0000

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