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| Message-ID | <4DFC928A.3050309@gmail.com> (permalink) |
|---|---|
| Date | 2011-06-18 13:56 +0200 |
| From | Francois Grieu <fgrieu@gmail.com> |
| Newsgroups | comp.lang.c |
| Subject | Re: filters |
| References | <87d3ibxx7e.fsf@yun.yagibdah.de> |
| Organization | Guest of ProXad - France |
On 18/06/2011 12:15, lee ask:
> How do you go about writing a filter, i. e. a program that reads
> data from stdin and processes it?
#include <stdio.h>
int main(void)
{
int c;
while(EOF!=(c = getchar()))
{
if (c>='0'&&c<='9')
c = '9'-c+'0';
putchar(c);
}
}
As an aside, I wonder if
c = '9'-c+'0'
is safe, and think
c = '9'+'0'-c
is not.
Francois Grieu
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filters lee <lee@yun.yagibdah.de> - 2011-06-18 12:15 +0200
Re: filters Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-18 11:37 +0100
Re: filters cri@tiac.net (Richard Harter) - 2011-06-18 18:42 +0000
Re: filters Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-18 23:13 +0100
Re: filters cri@tiac.net (Richard Harter) - 2011-06-19 19:02 +0000
Re: filters Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-19 21:16 +0100
Re: filters lee <lee@yun.yagibdah.de> - 2011-06-20 16:06 +0200
Re: filters Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-06-20 15:53 +0100
Re: filters lee <lee@yun.yagibdah.de> - 2011-06-27 22:20 +0200
Re: filters Francois Grieu <fgrieu@gmail.com> - 2011-06-18 13:56 +0200
Re: filters "Bill Cunningham" <nospam@nspam.invalid> - 2011-06-18 14:24 -0400
Re: filters Angel <angel+news@spamcop.net> - 2011-06-18 18:51 +0000
Re: filters Keith Thompson <kst-u@mib.org> - 2011-06-18 11:55 -0700
Re: filters Angel <angel+news@spamcop.net> - 2011-06-18 19:46 +0000
Re: filters Keith Thompson <kst-u@mib.org> - 2011-06-18 13:18 -0700
Re: filters Lew Pitcher <lpitcher@teksavvy.com> - 2011-06-18 14:55 -0400
Re: filters James Kuyper <jameskuyper@verizon.net> - 2011-06-18 10:14 -0400
Re: filters cri@tiac.net (Richard Harter) - 2011-06-18 19:58 +0000
Re: filters Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-19 16:09 -0700
Re: filters Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-06-20 07:51 +0000
Re: filters Tim Rentsch <txr@alumni.caltech.edu> - 2011-06-20 12:33 -0700
Re: filters Nobody <nobody@nowhere.com> - 2011-06-18 15:25 +0100
Re: filters gordonb.f4hvo@burditt.org (Gordon Burditt) - 2011-06-18 15:17 -0500
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