Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c > #139150
| From | "Rick C. Hodgin" <rick.c.hodgin@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c, comp.lang.c++ |
| Subject | Range-aware modulo operator -% |
| Date | 2018-12-27 21:09 -0500 |
| Organization | Liberty Software Foundation |
| Message-ID | <q040h4$bie$1@dont-email.me> (permalink) |
Cross-posted to 2 groups.
I think C/C++ needs to have a range-aware modulo operator that will
continue ranging properly when it encounters negative values.
We have this:
i = (i + 1) % 10; // Always ranges 0..9
But what if you try this when i = 0:
i = (i - 1) % 10;
It won't produce the same result in the same pattern seen when you
started at a positive i and tended toward 0. It begins a new trend,
one which is useful, but not always desirable.
A range-aware modulo operator would know that it should always be
in the range 0..9 (from the example above), and also that it should
continue the pattern seen in the positive integers, such that when
given a negative input value, it handles the processing differently:
// v=value, m=modulo number
int range_modulo(int v, int m)
{
if (v >= 0) return (v % m);
else return ((m + (v % m)) % m);
}
int i;
for (i = 12; i >= -12; --i)
printf("%d --> mod 10 = %d\n", i, range_modulo(i, 10));
-----
I propose the -% symbol for the operator.
It would allow things that are sometimes needed in video games,
as just one example, when a player hits the left button instead
of the right button, and you need it to go the other way, AND you
want it to just work while using the same math.
Just sayin'... :-)
--
Rick C. Hodgin
Back to comp.lang.c | Previous | Next — Next in thread | Find similar | Unroll thread
Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-27 21:09 -0500
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-27 21:34 -0500
Re: Range-aware modulo operator -% "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2018-12-28 05:37 +0100
Re: Range-aware modulo operator -% James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-29 16:04 -0500
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-29 19:13 -0500
Re: Range-aware modulo operator -% Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-28 03:05 +0000
Re: Range-aware modulo operator -% Robert Wessel <robertwessel2@yahoo.com> - 2018-12-27 21:31 -0600
Re: Range-aware modulo operator -% Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-28 04:20 +0000
Re: Range-aware modulo operator -% James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-27 19:32 -0800
Re: Range-aware modulo operator -% Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-12-28 04:18 +0000
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-28 12:29 +0000
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-28 08:10 -0500
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-28 10:25 -0500
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-28 15:56 +0000
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-28 17:26 -0500
Re: Range-aware modulo operator -% Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2018-12-28 23:45 +0100
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-28 11:44 -0500
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-28 12:16 -0500
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-28 17:08 -0500
Re: Range-aware modulo operator -% Tim Rentsch <txr@alumni.caltech.edu> - 2018-12-28 15:01 -0800
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-31 09:04 -0500
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-31 18:07 +0000
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-31 14:22 -0500
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-31 21:05 +0000
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-31 16:32 -0500
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-31 23:43 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2018-12-31 16:44 -0800
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-01 01:06 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2018-12-31 19:06 -0800
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-01 11:32 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2019-01-01 12:48 -0800
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-01 23:54 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2019-01-01 16:09 -0800
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-02 00:49 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2019-01-01 17:53 -0800
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-02 02:36 +0000
Leader Kiki is not going to like this... (Was: Range-aware modulo operator -%) gazelle@shell.xmission.com (Kenny McCormack) - 2019-01-02 08:36 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2019-01-02 00:38 -0800
Re: Range-aware modulo operator -% rbowman <bowman@montana.com> - 2019-01-01 22:40 -0700
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2019-01-02 12:12 +0000
Re: Range-aware modulo operator -% gazelle@shell.xmission.com (Kenny McCormack) - 2019-01-01 01:53 +0000
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-31 16:57 -0500
Re: Range-aware modulo operator -% Bart <bc@freeuk.com> - 2018-12-31 22:33 +0000
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2018-12-31 13:34 -0800
Re: Range-aware modulo operator -% Richard Damon <Richard@Damon-Family.org> - 2018-12-31 16:43 -0500
Re: Range-aware modulo operator -% Keith Thompson <kst-u@mib.org> - 2018-12-31 15:20 -0800
Re: Range-aware modulo operator -% Eduardo <abdulai60@gmail.com> - 2018-12-28 07:18 -0800
Re: Range-aware modulo operator -% "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-12-28 11:45 -0500
csiph-web