Re: Right trim string function in C

From	"Scott Fluhrer" <sfluhrer@ix.netcom.com>
Newsgroups	comp.lang.c
References	<jh3n08$6hs$1@speranza.aioe.org>
Subject	Re: Right trim string function in C
Message-ID	<1328906232.68669@rcdn-nntpcache-2> (permalink)
Organization	cisco.com
Date	2012-02-10 15:39 -0500

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"peter" <pc722@nospam.mail.com.br> wrote in message 
news:jh3n08$6hs$1@speranza.aioe.org...
> Hello C programmers,
>        I was wondering does anybody knows how or is there
> a right trim string function available in C?
>
>        Eg. Suppose I have the following:
>
>           char *str = "Hello Dolly     \0";
>
>        Is there a right trim function that will remove the
> trailing spaces and make *str look like "Hello Dolly\0"?

Other people have given you advice about how to do it (it isn't difficult), 
but they mentioned that the string must be in a "mutable buffer", without 
spelling out what that is.

Here's the issue; when you use a constant string using the "string" context, 
as in:

   char *str = "Hello Dolly     \0";

that string lies in memory that you're not supposed to modify.  If you do 
modify it, well, C doesn't say what happens; the compiler can do whatever it 
thinks is appropriate (which might not what you think is appropriate).  In 
practice, common behaviors could be:
- The program terminates (yes, really)
- The string is not changed, but the program continues anyways
- The string gets modified as you would expect
- The string gets modified, and in addition, other strings throughout the 
program also get modified

If you have such a string, and you want to modify it, you'll need to copy 
it, and modify the copy.

The exception to the above rule is if you declare str to be an array of 
char's, as:

    char str[] = "Hello Dolly     \0";

If you do that, you can modify str to your hearts content (as long as you 
don't write past the end of the array)...


Now, if you're doing this on nonfixed strings (say, strings you read from a 
file), well, this isn't an issue, or as a wise woman once said: "Never Mind"

-- 
poncho

Thread

Right trim string function in C peter <pc722@nospam.mail.com.br> - 2012-02-10 18:17 +0000
  Re: Right trim string function in C James Kuyper <jameskuyper@verizon.net> - 2012-02-10 13:36 -0500
    Re: Right trim string function in C Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-02-10 11:00 -0800
      Re: Right trim string function in C "BartC" <bc@freeuk.com> - 2012-02-14 12:41 +0000
        Re: Right trim string function in C "BartC" <bc@freeuk.com> - 2012-02-14 14:14 +0000
          Re: Right trim string function in C Ike Naar <ike@iceland.freeshell.org> - 2012-02-15 00:03 +0000
            Re: Right trim string function in C "BartC" <bc@freeuk.com> - 2012-02-15 01:00 +0000
              Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-15 02:08 +0000
              Re: Right trim string function in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-15 03:08 -0800
                Re: Right trim string function in C gazelle@shell.xmission.com (Kenny McCormack) - 2012-02-15 13:00 +0000
                Re: Right trim string function in C Kaz Kylheku <kaz@kylheku.com> - 2012-02-16 00:36 +0000
              Re: Right trim string function in C Kaz Kylheku <kaz@kylheku.com> - 2012-02-16 00:28 +0000
              Re: Right trim string function in C gordonb.7bjv1@burditt.org (Gordon Burditt) - 2012-03-12 03:27 -0500
                Re: Right trim string function in C China Blue Water Navy <chine.bleu@yahoo.com> - 2012-03-12 03:57 -0800
        Re: Right trim string function in C Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-02-14 09:59 -0800
      Re: Right trim string function in C Kaz Kylheku <kaz@kylheku.com> - 2012-02-14 12:56 +0000
        Re: Right trim string function in C Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-02-14 09:17 -0800
        Re: Right trim string function in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-14 10:10 -0800
  Re: Right trim string function in C Barry Schwarz <schwarzb@dqel.com> - 2012-02-10 11:30 -0800
    Re: Right trim string function in C James Kuyper <jameskuyper@verizon.net> - 2012-02-10 14:45 -0500
      Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-10 22:15 +0000
        Re: Right trim string function in C James Kuyper <jameskuyper@verizon.net> - 2012-02-10 17:21 -0500
          Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-10 23:25 +0000
          Re: Right trim string function in C Keith Thompson <kst-u@mib.org> - 2012-02-10 15:31 -0800
      Re: Right trim string function in C pete <pfiland@mindspring.com> - 2012-02-10 17:17 -0500
        Re: Right trim string function in C Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-02-10 15:12 -0800
  Re: Right trim string function in C "Morris Keesan" <mkeesan@post.harvard.edu> - 2012-02-10 14:46 -0500
    Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-10 21:56 +0000
      Re: Right trim string function in C James Kuyper <jameskuyper@verizon.net> - 2012-02-10 17:08 -0500
        Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-10 23:14 +0000
          Re: Right trim string function in C David Thompson <dave.thompson2@verizon.net> - 2012-02-18 23:11 -0500
      Re: Right trim string function in C Keith Thompson <kst-u@mib.org> - 2012-02-11 12:06 -0800
      Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-11 20:12 +0000
      Re: Right trim string function in C Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-08 13:10 -0800
  Re: Right trim string function in C "Scott Fluhrer" <sfluhrer@ix.netcom.com> - 2012-02-10 15:39 -0500
  Re: Right trim string function in C Shao Miller <sha0.miller@gmail.com> - 2012-02-11 03:52 -0500
    Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-11 13:50 +0000
      Re: Right trim string function in C Shao Miller <sha0.miller@gmail.com> - 2012-02-11 11:47 -0500
        Re: Right trim string function in C Shao Miller <sha0.miller@gmail.com> - 2012-02-11 12:20 -0500
        Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-11 20:57 +0000
          Re: Right trim string function in C Shao Miller <sha0.miller@gmail.com> - 2012-02-11 17:43 -0500
  Re: Right trim string function in C Willem <willem@toad.stack.nl> - 2012-02-11 11:57 +0000
    Re: Right trim string function in C Willem <willem@toad.stack.nl> - 2012-02-11 18:11 +0000
  Re: Right trim string function in C August Karlstrom <fusionfile@gmail.com> - 2012-02-11 18:41 +0100
    Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-11 19:58 +0000
      Re: Right trim string function in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-11 13:11 -0800
      Re: Right trim string function in C August Karlstrom <fusionfile@gmail.com> - 2012-02-11 22:18 +0100
        Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-11 23:48 +0000
          Re: Right trim string function in C August Karlstrom <fusionfile@gmail.com> - 2012-02-12 02:20 +0100
          Re: Right trim string function in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-12 03:44 -0800
            Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-12 14:01 +0000
              Re: Right trim string function in C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-12 11:06 -0800
                Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-12 19:34 +0000
                Re: Right trim string function in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-02-12 23:35 +0000
    Re: Right trim string function in C Barry Schwarz <schwarzb@dqel.com> - 2012-02-11 14:27 -0800
      Re: Right trim string function in C August Karlstrom <fusionfile@gmail.com> - 2012-02-12 14:40 +0100

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