NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c-part2/12837

Internet Message Format | 1996-08-05 | 2.2 KB

Path: mail2news.demon.co.uk!genesis.demon.co.uk
From: Lawrence Kirby <[e-mail]>
Newsgroups: comp.lang.c,comp.unix.programmer
Subject: Re: Q: '\n' character
Date: Wed, 03 Apr 96 01:01:59 GMT
Organization: none
Message-ID: <[e-mail]>
References: <[e-mail]> <4jrvv3$[e-mail]>
Reply-To: [e-mail]
X-NNTP-Posting-Host: genesis.demon.co.uk
X-Newsreader: Demon Internet Simple News v1.27
X-Mail2News-Path: genesis.demon.co.uk

In article <4jrvv3$[e-mail]>
           [e-mail] "Jonathan S. McNeill" writes:

>In article <[e-mail]>,
>Artur Wojdat  <[e-mail]> wrote:
>
>>       Is there a function or some sort of way that I could remove '\n'
>>charecter form the end of the string. I'm reading from two files, want to
>>form one line of text and then have it printed out to stdout. I use fgets to
>>read from the file and I noticed that it appends newline char at the end.

The newline character is in the input stream, fgets() simply doesn't
discard it like gets() does.

>/*
> * loop through characters until newline or end of file
> */
>while ( (ch = getc(stream)) != '\n' && ch != EOF ) {
>
>        sprintf(buffer, "%s%c", buffer, ch);

This is truely horrific. You can't read and write to the same object with
sprintf - the result is undefined behaviour. %s requires that you pass
as the corresponding argument a pointer to a properly null character
terminated string. There is no indication that buffer holds such a thing
here.

>}
>
>/*
> * add a trailing nul character so that you can use string functions
> */
>sprintf(buffer, "%s\0");

As far as a string is concerned "%s\0" is no different from "%s". There
is an extra null character in there but a string always terminates at the
first one so sprintf never sees the 2nd one. Also there's no argument
corresponding to %s.

There is a simple trick to remove any trailing newline character in a string
typically written by fgets(), say into buffer,  and that is:

   strtok(buffer, "\n");

--
-----------------------------------------
Lawrence Kirby | [e-mail]
Wilts, England | [e-mail]
-----------------------------------------