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Groups > comp.lang.c > #126736
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Text Files |
| Date | 2018-02-15 16:05 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <87fu628cib.fsf@bsb.me.uk> (permalink) |
| References | <5a8459d1$0$707$14726298@news.sunsite.dk> <p648nf02rlq@news2.newsguy.com> |
"F. Russell" <fr@random.info> writes: > On Wed, 14 Feb 2018 11:47:00 -0400, G B wrote: > >> what is the best way to read numbers >> line by line and do some tests on numbers for that line before moving to >> the next line? for example the text file might be: >> >> 07 23 36 52 53 57 > > The best way is NOT to read the file line by line. The I/O > overhead is a problem. How do you know that? > Read the entire file into memory and then process. As you have sketched it, this method has it's own problems. The one I'd be most concerned about is that you can't pipe data to it. I often find I want to write program to generate or filter or otherwise pre-process the data and going through a file every time is a pain. If you are doing the sort of investigative data analysis that I often find myself doing, you want a flexible, pluggable set of tools. > Here is just a program fragment: > > char *buffer; > long file_size; > > FILE *fd = fopen(argv[1], "rb"); > fseek(fd, 0, SEEK_END); > file_size = ftell(fd); > rewind(fd); > buffer=malloc(file_size *(sizeof(char))); sizeof (char) is guaranteed to be 1. It's not wrong to use it, of course, but I always wonder about why the author put it there and that slows me down a bit. I'd add one to the size and then null-terminate the array so as to have the file contents as a string. You've got the probable size, so you don't need to, but it makes the processing loop easier if it's a string. > fread(buffer, sizeof(char), file_size, fd); > fclose(fd); > > Now you can step through the buffer and process > the numbers. Since the file was read as binary data, you will have to manage the line endings yourself if the program is intended to be portable. It's likely this one isn't, and also likely that differences in line endings can be ignored, so this is not a big problem. -- Ben.
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Text Files G B <gb@gb.com> - 2018-02-14 11:47 -0400
Re: Text Files Ed Prochak <edprochak@gmail.com> - 2018-02-14 08:45 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-14 08:47 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-15 01:17 -0800
Re: Text Files gordonb.ea2mq@burditt.org (Gordon Burditt) - 2018-02-14 11:10 -0600
Re: Text Files "James R. Kuyper" <jameskuyper@verizon.net> - 2018-02-14 12:28 -0500
Re: Text Files jt@toerring.de (Jens Thoms Toerring) - 2018-02-14 21:07 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-14 15:31 -0700
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-15 06:59 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 10:20 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-14 22:51 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 11:04 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-15 06:16 -0800
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:22 +0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 15:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 16:31 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:31 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:21 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:17 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:36 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:48 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:09 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:57 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 15:50 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 15:50 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:07 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:44 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:22 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 17:48 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-16 17:06 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:10 +1300
Re: Text Files supercat@casperkitty.com - 2018-02-16 14:48 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-16 15:14 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 23:25 +0000
Re: Text Files supercat@casperkitty.com - 2018-02-16 15:50 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-16 07:19 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:13 +0100
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-19 17:55 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-19 19:14 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-19 11:48 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 08:14 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-17 18:32 -0600
Re: Text Files jacobnavia <jacob@jacob.remcomp.fr> - 2018-02-15 22:57 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:58 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 00:19 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 02:26 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 02:57 +0000
Re: Text Files asetofsymbols@gmail.com - 2018-02-16 00:21 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:30 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:36 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:36 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 13:10 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:25 +0000
Re: Text Files Ike Naar <ike@iceland.freeshell.org> - 2018-03-06 19:33 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-03-06 20:55 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:42 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 16:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:02 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 21:43 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:01 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 13:10 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 05:27 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 14:20 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-16 09:04 -0700
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 14:31 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 06:42 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 14:58 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 07:23 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 15:24 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:13 -0800
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-16 04:29 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 16:41 +0000
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-20 09:39 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 19:16 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 12:46 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 14:52 +0100
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 17:07 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 14:23 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 18:52 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 14:39 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 15:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 20:32 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 22:06 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 23:12 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 15:12 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:54 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:35 +0000
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-16 17:07 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 02:38 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 17:26 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 11:22 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 12:07 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:17 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-17 16:25 +0300
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 07:35 -0800
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-17 15:24 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-18 11:10 +1300
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-19 12:05 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-19 15:32 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 10:34 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-21 15:35 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-22 00:11 +0000
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-21 18:26 -0600
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 21:39 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-23 03:08 -0600
Re: Text Files supercat@casperkitty.com - 2018-02-23 16:16 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-23 16:46 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-24 02:49 -0800
Re: Text Files asetofsymbols@gmail.com - 2018-02-24 05:16 -0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-24 14:35 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-24 08:48 -0700
Re: Text Files supercat@casperkitty.com - 2018-02-25 15:09 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:54 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 11:04 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 11:52 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 14:12 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 14:40 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-22 04:58 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 05:33 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-22 13:59 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 07:24 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-20 12:14 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:37 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:34 +0000
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 14:15 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:47 +0100
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:20 +0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-15 15:24 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 16:05 +0000
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-16 00:22 +0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-15 13:35 -0700
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 00:13 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-24 21:24 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 14:55 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 13:00 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:35 -0400
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 21:36 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:45 -0400
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-24 22:51 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 23:56 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:14 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:22 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:16 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:20 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-25 20:27 -0700
Re: Text Files gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 06:19 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 15:35 +0300
Re: Text Files Reinhardt Behm <rbehm@hushmail.com> - 2018-02-26 20:53 +0800
Grammar Patrol (Was: Text Files) gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 17:54 +0000
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-26 15:27 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 18:50 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:26 -0800
Re: Text Files scott@slp53.sl.home (Scott Lurndal) - 2018-02-26 19:46 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 09:04 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 00:56 -0800
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-27 22:07 +1300
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 14:37 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 07:38 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-27 09:18 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 10:15 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-27 08:53 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 23:14 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-26 08:32 -0700
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:17 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 22:55 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:02 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-25 20:12 +0000
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