Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #15972

Re: C arithmetic question.

Show all headers | View raw

Keith Thompson <kst-u@mib.org> writes:

> Michael Press <rubrum@pacbell.net> writes:
> [...]
>> There is nothing to gain by learning C's idiosyncratic
>> rules on integer types for the purpose of doing arithmetic.
>
> You could gain the ability to write C code that does arithmetic.  The
> vast majority of people have chosen not to learn it, but your presence
> in this newsgroup suggests that you might find it useful.

The main thing is that there aren't that many occasions when you need to
mix signed and unsigned numbers, and that's when unexpected -  to the
naive programmer - things can happen.

The rest of the time there's nothing special going on.

I tend to use the odd (probably) superfluous cast in those
circumstances: it makes it clear to me what I wanted to happen and to
anyone else reading the code.  I'd need to double check what I wanted,
and document it with a comment anyway.

But even in programs using both signed and unsigned numbers the two mix
only infrequently.  GCC is pretty good at warning when you've written
something that doesn't do what you might have thought it would.
-- 
Online waterways route planner            | http://canalplan.eu
Plan trips, see photos, check facilities  | http://canalplan.org.uk

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-18 10:32 -0800
  Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-18 14:03 -0500
    Re: C arithmetic question. TheGunslinger <mikiesrunsbaal.sec@sbcglobal.net> - 2012-01-18 19:30 -0800
      Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-19 08:10 -0500
  Re: C arithmetic question. Markus Wichmann <nullplan@gmx.net> - 2012-01-18 21:14 +0100
    Re: C arithmetic question. "BartC" <bc@freeuk.com> - 2012-01-19 10:44 +0000
      Re: C arithmetic question. Seebs <usenet-nospam@seebs.net> - 2012-01-21 21:32 +0000
  Re: C arithmetic question. Peter Nilsson <airia@acay.com.au> - 2012-01-18 13:51 -0800
    Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-18 15:51 -0800
      Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-18 20:50 -0500
        Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-20 12:41 -0800
          Re: C arithmetic question. Keith Thompson <kst-u@mib.org> - 2012-01-20 14:11 -0800
            Re: C arithmetic question. gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-20 22:43 +0000
          Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-20 17:19 -0500
            Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-20 17:32 -0500
              And jacob navia <jacob@spamsink.net> - 2012-01-20 23:52 +0100
                Re: And Markus Wichmann <nullplan@gmx.net> - 2012-01-21 19:23 +0100
                Re: And Keith Thompson <kst-u@mib.org> - 2012-01-21 13:20 -0800
                Re: And jacob navia <jacob@spamsink.net> - 2012-01-21 23:02 +0100
                Re: And Markus Wichmann <nullplan@gmx.net> - 2012-01-22 15:24 +0100
                Re: And Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-22 15:40 +0000
                Re: And blp@cs.stanford.edu (Ben Pfaff) - 2012-01-21 11:02 -0800
          Re: C arithmetic question. Rui Maciel <rui.maciel@gmail.com> - 2012-01-24 18:53 +0000
      Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-19 02:09 +0000
      Re: C arithmetic question. Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-18 23:00 -0700
        Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-18 23:14 -0800
          Re: C arithmetic question. Ike Naar <ike@sverige.freeshell.org> - 2012-01-19 08:41 +0000
            Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-20 12:43 -0800
              Re: C arithmetic question. Kaz Kylheku <kaz@kylheku.com> - 2012-01-20 22:17 +0000
                Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-21 00:12 -0800
              Re: C arithmetic question. Seebs <usenet-nospam@seebs.net> - 2012-01-21 21:32 +0000
                Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-21 23:21 +0000
                Re: C arithmetic question. Robert Wessel <robertwessel2@yahoo.com> - 2012-01-22 00:48 -0600
                Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-22 11:45 +0000
                Re: C arithmetic question. Robert Wessel <robertwessel2@yahoo.com> - 2012-01-22 21:46 -0600
                Re: C arithmetic question. Kaz Kylheku <kaz@kylheku.com> - 2012-01-23 04:17 +0000
                Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-23 11:19 +0000
                Re: C arithmetic question. Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-26 10:41 -0800
                Re: C arithmetic question. Seebs <usenet-nospam@seebs.net> - 2012-01-23 07:58 +0000
                Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-23 11:06 +0000
                Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-23 07:03 -0500
                Re: C arithmetic question. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-23 17:27 +0000
          Re: C arithmetic question. Keith Thompson <kst-u@mib.org> - 2012-01-19 02:38 -0800
            Re: C arithmetic question. Dr Nick <3-nospam@temporary-address.org.uk> - 2012-01-20 07:30 +0000
          Re: C arithmetic question. Nomen Nescio <nobody@dizum.com> - 2012-01-19 12:28 +0100
            Re: C arithmetic question. Michael Press <rubrum@pacbell.net> - 2012-01-20 12:44 -0800
              Re: C arithmetic question. 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-20 13:14 -0800
          Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-19 08:45 -0500
          Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 08:14 -0800
            Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-24 12:15 -0500
              Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 09:26 -0800
                Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-24 12:39 -0500
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 10:03 -0800
                Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-24 13:23 -0500
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 10:40 -0800
                Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-24 14:35 -0500
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 12:04 -0800
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 12:02 -0800
                Re: C arithmetic question. Kleuske <kleuske@nowhere.net> - 2012-01-24 20:26 +0000
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 13:45 -0800
                Re: C arithmetic question. James Kuyper <jameskuyper@verizon.net> - 2012-01-24 15:40 -0500
                Re: C arithmetic question. Chad <cdalten@gmail.com> - 2012-01-24 12:09 -0800
      Re: C arithmetic question. Rui Maciel <rui.maciel@gmail.com> - 2012-01-24 18:48 +0000
    Re: C arithmetic question. "osmium" <r124c4u102@comcast.net> - 2012-01-19 08:12 -0600
  Re: C arithmetic question. Geoff <geoff@invalid.invalid> - 2012-01-20 15:33 -0800
    Re: C arithmetic question. Kleuske <kleuske@nowhere.net> - 2012-01-27 08:17 +0000
      Re: C arithmetic question. Geoff <geoff@invalid.invalid> - 2012-01-27 13:37 -0800

csiph-web