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Groups > comp.lang.c > #66370

Re: counting bytes

From bartekltg <bartekltg@gmail.com>
Newsgroups comp.lang.c
Subject Re: counting bytes
Date 2015-07-26 00:58 +0200
Organization ATMAN - ATM S.A.
Message-ID <mp14au$qq7$1@node2.news.atman.pl> (permalink)
References <mkun7o$pc2$1@dont-email.me>

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On 06.06.2015 13:58, bilsch01 wrote:
> The code below writes a file to disk that has 52 bytes.  There are 4
> float and 8 int.  Isn't that 4x4 + 8x2 = 32 bytes?  I don't get it.

Your int is small ;-)

>
> When I change %i to %u the total is 56 bytes.  I think it should be the
> same whether %i or %u.
>
> int main(){
>
> int xf=65535, yf=0, xof=65535,  yof=0, xm=65535, ym=0, delay=0,
> glength=65535;
> float w1=0.5, w2=2.0, w3=0.14159, k1=.01;
> FILE *fp;
>
> fp = fopen("gdata", "w");
> fprintf(fp,"%f%f%f%f%i%i%i%i%i%i%i%i",w1,w2,w3,k1,xf,yf,xof,yof,xm,ym,delay,glength);
>
> fclose(fp);
> }


Did you look to the file? It looks like that:
0.5000002.0000000.1415900.010000655350655350655350065535
A binary representation of 4 floats and 8 ints have 32 bytes total.
But you do not write boinary data, fou convert numbers to "strings"
and write it to file. And text format usualy need more bytes than
binary one to contain a number.

This is one of proper ways:

#include <stdio.h>
#include <stdlib.h>

int main(){

     int xf=65535, yf=0, xof=65535,  yof=0, xm=65535, ym=0, delay=0, 
glength=65535;
     float w1=0.5, w2=2.0, w3=0.14159, k1=.01;
     FILE *fp;

     int  ti[8] = {xf, yf, xof,  yof, xm, ym, delay, glength};
     float tf[8]={w1,w2,w3,k1}; // fwrite writes compact chunk of data, 
you can call it 12 times or make these arrays.

     fp = fopen("gdata2", "wb");  //mode have a 'b'

     fwrite(ti,8,sizeof(int), fp);
     fwrite(tf,4,sizeof(float), fp);

     fclose(fp);
}

And now gdata2 have 48bytes ( 4-byte int in linux) and
looks like binary data, not numbers.

bartekltg




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counting bytes bilsch01 <king621@comcast.net> - 2015-06-06 04:58 -0700
  Re: counting bytes Bartc <bc@freeuk.com> - 2015-06-06 13:05 +0100
    Re: counting bytes bilsch01 <king621@comcast.net> - 2015-06-06 05:24 -0700
      Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-06-06 05:41 -0700
        Re: counting bytes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-06 14:00 +0100
      Re: counting bytes Bartc <bc@freeuk.com> - 2015-06-06 13:52 +0100
      Re: counting bytes Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-06-06 10:27 -0400
        Re: counting bytes jt@toerring.de (Jens Thoms Toerring) - 2015-06-06 22:31 +0000
          THANKS EVERYBODY FOR THE INFO bilsch01 <king621@comcast.net> - 2015-06-06 23:35 -0700
            Re: THANKS EVERYBODY FOR THE INFO Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-07 10:08 +0100
              Re: THANKS EVERYBODY FOR THE INFO Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-06-07 09:22 -0700
                Re: THANKS EVERYBODY FOR THE INFO Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-07 18:07 +0100
                Re: THANKS EVERYBODY FOR THE INFO Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-06-08 04:03 -0700
                Re: THANKS EVERYBODY FOR THE INFO Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-11 08:12 -0700
            Re: THANKS EVERYBODY FOR THE INFO Keith Thompson <kst-u@mib.org> - 2015-06-07 08:01 -0700
          Re: counting bytes gordonb.3gcai@burditt.org (Gordon Burditt) - 2015-06-07 05:02 -0500
          Re: counting bytes David Brown <david.brown@hesbynett.no> - 2015-06-07 15:32 +0200
            Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-06-07 12:48 -0700
              Re: counting bytes David Brown <david.brown@hesbynett.no> - 2015-06-07 23:05 +0200
                Re: counting bytes Richard Heathfield <rjh@cpax.org.uk> - 2015-06-07 22:17 +0100
                Re: counting bytes David Brown <david.brown@hesbynett.no> - 2015-06-07 23:49 +0200
                Re: counting bytes Richard Heathfield <rjh@cpax.org.uk> - 2015-06-07 23:37 +0100
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-11 08:25 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-11 08:21 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-11 13:54 -0500
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-20 06:33 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-20 09:51 -0500
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-24 09:49 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-24 12:26 -0500
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-30 11:16 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-30 23:15 -0500
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-02 06:07 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-02 14:31 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-09 05:31 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-09 17:09 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-05 09:58 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-09-05 19:29 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 14:38 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-09-06 17:46 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-07 23:50 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-09-06 22:00 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-07 23:24 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-24 20:03 -0400
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-24 22:13 -0500
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 02:22 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-25 11:39 -0500
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 09:48 -0700
                Re: counting bytes Martin Shobe <martin.shobe@yahoo.com> - 2015-07-25 14:04 -0500
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 14:22 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-25 11:07 -0400
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-25 12:43 -0400
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-25 13:32 -0400
                Re: counting bytes glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-25 20:14 +0000
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-25 17:24 -0400
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 14:42 -0700
                Re: counting bytes glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-25 23:02 +0000
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-25 19:17 -0400
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-25 16:37 -0700
                Re: counting bytes glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-26 06:10 +0000
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-26 08:31 -0400
                Re: counting bytes Bartc <bc@freeuk.com> - 2015-07-30 21:32 +0100
                Re: counting bytes raltbos@xs4all.nl (Richard Bos) - 2015-07-31 13:25 +0000
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-31 11:31 -0400
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-31 11:30 -0700
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-31 14:29 -0400
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-31 12:14 -0700
                Re: counting bytes David Kleinecke <dkleinecke@gmail.com> - 2015-07-31 17:39 -0700
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-31 23:32 -0400
                Re: counting bytes David Kleinecke <dkleinecke@gmail.com> - 2015-08-01 16:41 -0700
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-08-01 20:23 -0400
                Re: counting bytes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-07-31 11:01 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-25 19:42 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-30 12:16 -0700
                Re: counting bytes Bartc <bc@freeuk.com> - 2015-07-30 22:04 +0100
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-02 06:10 -0700
                Re: counting bytes David Kleinecke <dkleinecke@gmail.com> - 2015-07-25 19:10 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-25 22:16 -0400
                Re: counting bytes David Kleinecke <dkleinecke@gmail.com> - 2015-07-25 19:46 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-30 11:52 -0700
                Re: counting bytes raltbos@xs4all.nl (Richard Bos) - 2015-07-31 08:51 +0000
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-02 06:19 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-01 09:39 -0400
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-08-01 13:06 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-01 20:43 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-02 06:52 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-02 15:14 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-09 07:54 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-08-09 16:43 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-05 10:48 -0700
                Re: counting bytes Richard Damon <Richard@Damon-Family.org> - 2015-07-11 17:50 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-20 06:36 -0700
                Re: counting bytes raltbos@xs4all.nl (Richard Bos) - 2015-07-20 15:14 +0000
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-24 09:38 -0700
                Re: counting bytes raltbos@xs4all.nl (Richard Bos) - 2015-07-25 19:12 +0000
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-30 12:18 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-11 17:03 -0700
                Re: counting bytes glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-12 00:15 +0000
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-11 17:42 -0700
                Re: counting bytes glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-07-12 02:46 +0000
                Re: counting bytes James Kuyper <jameskuyper@verizon.net> - 2015-07-12 12:33 -0400
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-20 06:48 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-20 11:18 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-24 09:58 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-24 11:14 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-07-30 11:02 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-07-30 13:10 -0700
                Re: counting bytes Tim Rentsch <txr@alumni.caltech.edu> - 2015-08-01 10:53 -0700
                Re: counting bytes Keith Thompson <kst-u@mib.org> - 2015-06-07 14:46 -0700
                Re: counting bytes David Brown <david.brown@hesbynett.no> - 2015-06-08 09:05 +0200
  Re: counting bytes Siri Cruz <chine.bleu@yahoo.com> - 2015-06-06 05:06 -0700
  Re: counting bytes bartekltg <bartekltg@gmail.com> - 2015-07-26 00:58 +0200
    Re: counting bytes bartekltg <bartekltg@gmail.com> - 2015-07-26 01:00 +0200

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