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Groups > comp.lang.c > #123610
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Toy code for currency handling |
| Date | 2017-11-29 09:25 -0800 |
| Organization | None to speak of |
| Message-ID | <lnvahtxai3.fsf@kst-u.example.com> (permalink) |
| References | (1 earlier) <ov6hef02etp@news3.newsguy.com> <ov8m5j$vn9$1@dont-email.me> <ov99nf$5uc$1@jstuckle.eternal-september.org> <ovm3di$vgs$1@dont-email.me> <ovmirc$cs7$1@dont-email.me> |
Noob <root@127.0.0.1> writes:
> On 29/11/2017 11:50, Noob wrote:
>
>> 2**64 = 1.8e19
>> Using one millionth dollars as the base unit, we can express
>> values from 0 to 18000 billion dollars.
>>
>> But I guess this doesn't solve rounding issues, which have to
>> be dealt with when multiplying.
>>
>> I'll write a toy program to experiment with that :-)
>
> I played around with a different approach: storing the integral part
> in a u64, and the fractional part (in billionth) in a u32 (effectively
> ~94 significant bits). I'm still not quite sure how to handle rounding.
[...]
As I understand it, there are specific rules, in laws and/or
regulations, that govern exactly how rounding is to be performed.
I have no idea what those rules are (I've never particularly needed
to know). If I were going to work on production software that
deals with money, I'd have to learn them.
If you're writing something for your own use, say to balance your
checkbook, and a 1-cent error on an interest calculation isn't fatal,
you probably don't need to worry about it.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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[computerphile] Why can't floating point do money? luser droog <luser.droog@gmail.com> - 2017-11-22 09:39 -0800
Re: [computerphile] Why can't floating point do money? "F. Russell" <fr@random.info> - 2017-11-23 13:11 +0000
Re: [computerphile] Why can't floating point do money? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-23 05:35 -0800
Re: [computerphile] Why can't floating point do money? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-11-23 13:47 +0000
Re: [computerphile] Why can't floating point do money? "F. Russell" <fr@random.info> - 2017-11-23 15:20 +0000
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-24 00:53 -0600
Re: [computerphile] Why can't floating point do money? supercat@casperkitty.com - 2017-11-24 14:16 -0800
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-24 23:50 -0600
Re: [computerphile] Why can't floating point do money? Noob <root@127.0.0.1> - 2017-11-24 09:44 +0100
Re: [computerphile] Why can't floating point do money? Jerry Stuckle <jstucklex@attglobal.net> - 2017-11-24 09:18 -0500
Re: [computerphile] Why can't floating point do money? Noob <root@127.0.0.1> - 2017-11-29 11:50 +0100
Re: Toy code for currency handling Noob <root@127.0.0.1> - 2017-11-29 16:13 +0100
Re: Toy code for currency handling Noob <root@127.0.0.1> - 2017-11-29 16:53 +0100
Re: Toy code for currency handling Robert Wessel <robertwessel2@yahoo.com> - 2017-11-29 10:42 -0600
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-11-29 09:25 -0800
Re: Toy code for currency handling Noob <root@127.0.0.1> - 2017-11-29 19:38 +0100
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-11-29 11:03 -0800
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-11-29 19:14 +0000
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-11-29 11:31 -0800
Re: Toy code for currency handling Robert Wessel <robertwessel2@yahoo.com> - 2017-12-01 00:04 -0600
Re: Toy code for currency handling fr314159@gmail.com - 2017-12-01 12:41 -0800
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-01 15:24 -0800
Re: Toy code for currency handling Noob <root@127.0.0.1> - 2017-12-03 18:08 +0100
Re: Toy code for currency handling fr314159@gmail.com - 2017-12-04 10:06 -0800
Re: Toy code for currency handling jameskuyper@verizon.net - 2017-12-04 10:19 -0800
Re: Toy code for currency handling fr314159@gmail.com - 2017-12-04 11:35 -0800
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-04 11:56 -0800
Re: Toy code for currency handling Jerry Stuckle <jstucklex@attglobal.net> - 2017-12-04 15:01 -0500
Re: Toy code for currency handling "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-12-05 07:14 +0100
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-05 09:18 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 11:31 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-05 14:13 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 14:39 +0000
Re: Toy code for currency handling Melzzzzz <Melzzzzz@zzzzz.com> - 2017-12-05 15:00 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 15:19 +0000
Re: Toy code for currency handling Melzzzzz <mel@zzzzz.com> - 2017-12-05 16:31 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 16:07 +0000
Re: Toy code for currency handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-12-06 01:25 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 02:00 +0000
Re: Toy code for currency handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-12-06 03:04 +0000
Re: Toy code for currency handling scott@slp53.sl.home (Scott Lurndal) - 2017-12-05 16:14 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-05 17:28 +0100
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-05 11:25 -0800
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 21:47 +0000
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-05 14:13 -0800
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 22:40 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 00:38 +0100
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 00:21 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 02:22 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 10:04 +0100
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-06 08:31 -0800
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-05 16:25 +0100
Re: Toy code for currency handling already5chosen@yahoo.com - 2017-12-05 08:33 -0800
Re: Toy code for currency handling Melzzzzz <Melzzzzz@zzzzz.com> - 2017-12-05 19:09 +0000
Re: Toy code for currency handling already5chosen@yahoo.com - 2017-12-05 12:27 -0800
Re: Toy code for currency handling Melzzzzz <Melzzzzz@zzzzz.com> - 2017-12-05 20:40 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 16:42 +0000
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-05 09:39 -0800
Re: Toy code for currency handling scott@slp53.sl.home (Scott Lurndal) - 2017-12-05 17:52 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-06 07:59 +1300
Re: Toy code for currency handling Melzzzzz <Melzzzzz@zzzzz.com> - 2017-12-05 19:12 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-05 21:59 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 00:44 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 01:52 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-06 19:40 +1300
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 12:03 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 10:30 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 11:40 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 14:03 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 14:32 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-06 16:25 +0100
Re: Toy code for currency handling already5chosen@yahoo.com - 2017-12-06 07:47 -0800
Re: Toy code for currency handling scott@slp53.sl.home (Scott Lurndal) - 2017-12-06 16:06 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 18:08 +0000
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-06 11:22 -0800
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-06 09:24 -0800
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-06 11:23 -0800
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-06 11:18 -0800
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 19:59 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 20:02 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-07 09:39 +1300
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 21:36 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-07 11:15 +1300
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 23:36 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-07 12:49 +1300
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-06 23:58 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-07 13:08 +1300
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 01:51 +0000
Re: Toy code for currency handling Ian Collins <ian-news@hotmail.com> - 2017-12-07 14:54 +1300
Re: Toy code for currency handling Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-12-07 11:27 -0500
Re: Toy code for currency handling Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2017-12-07 03:38 +0100
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-06 20:39 -0800
Re: Toy code for currency handling "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-12-07 12:45 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 12:21 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-07 14:53 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 14:31 +0000
Re: Toy code for currency handling "Pascal J. Bourguignon" <pjb@informatimago.com> - 2017-12-07 15:33 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 14:53 +0000
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 14:46 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-07 20:28 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 20:03 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-07 22:27 +0100
Re: Toy code for currency handling bartc <bc@freeuk.com> - 2017-12-07 22:45 +0000
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-08 00:39 +0100
Re: Toy code for currency handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-12-07 21:38 +0000
Re: Toy code for currency handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-12-07 15:24 +0000
Re: Toy code for currency handling supercat@casperkitty.com - 2017-12-07 07:42 -0800
Re: Toy code for currency handling scott@slp53.sl.home (Scott Lurndal) - 2017-12-07 14:58 +0000
Re: Toy code for currency handling already5chosen@yahoo.com - 2017-12-06 01:45 -0800
Re: Toy code for currency handling Jerry Stuckle <jstucklex@attglobal.net> - 2017-12-05 08:38 -0500
Re: Toy code for currency handling "James R. Kuyper" <jameskuyper@verizon.net> - 2017-12-04 15:16 -0500
Re: Toy code for currency handling asetofsymbols@gmail.com - 2017-12-05 02:56 -0800
Re: Toy code for currency handling Keith Thompson <kst-u@mib.org> - 2017-12-04 11:04 -0800
Re: Toy code for currency handling David Brown <david.brown@hesbynett.no> - 2017-12-05 09:33 +0100
Re: Toy code for currency handling Jerry Stuckle <jstucklex@attglobal.net> - 2017-12-04 14:56 -0500
Re: Toy code for currency handling Robert Wessel <robertwessel2@yahoo.com> - 2017-12-04 20:44 -0600
Re: Toy code for currency handling herrmannsfeldt@gmail.com - 2017-12-06 21:59 -0800
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-29 10:51 -0600
Re: [computerphile] Why can't floating point do money? Jerry Stuckle <jstucklex@attglobal.net> - 2017-11-30 16:18 -0500
Re: [computerphile] Why can't floating point do money? scott@slp53.sl.home (Scott Lurndal) - 2017-11-30 22:13 +0000
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-24 10:19 -0600
Re: [computerphile] Why can't floating point do money? Spiros Bousbouras <spibou@gmail.com> - 2017-11-24 16:43 +0000
Re: [computerphile] Why can't floating point do money? "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2017-11-24 08:53 -0800
Re: [computerphile] Why can't floating point do money? bert <bert.hutchings@btinternet.com> - 2017-11-24 08:57 -0800
Re: [computerphile] Why can't floating point do money? bartc <bc@freeuk.com> - 2017-11-24 16:57 +0000
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-24 23:35 -0600
Re: [computerphile] Why can't floating point do money? Melzzzzz <Melzzzzz@zzzzz.com> - 2017-11-25 05:59 +0000
Re: [computerphile] Why can't floating point do money? supercat@casperkitty.com - 2017-11-27 10:14 -0800
Re: [computerphile] Why can't floating point do money? Robert Wessel <robertwessel2@yahoo.com> - 2017-11-30 23:56 -0600
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