Re: How to use a struct with qsort()?

Subject	Re: How to use a struct with qsort()?
Newsgroups	comp.lang.c
References	(3 earlier) <06add10e-1e30-4741-a20c-ff56363733fe@googlegroups.com> <BkKqF.69070$1A2.65981@fx07.iad> <qovf0n$1lfh$1@gioia.aioe.org> <kUUsF.1229971$WI2.370840@fx34.am4> <qp1mtt$1f9h$1@gioia.aioe.org>
From	DFS <nospam@dfs.com>
Message-ID	<vC3tF.55417$SW2.31092@fx24.iad> (permalink)
Organization	blocknews - www.blocknews.net
Date	2019-10-26 18:17 -0400

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On 10/26/2019 10:58 AM, Manfred wrote:

> There can be much more to be said about the complete program 

Please, speak up.  Won't hurt my feelings.

> (the OP's memory management mistakes 

Feel free to show them.  I want to get it as right as possible.

> and his/her remark about books being 
> unhelpful suggest limited knowledge of C) 

Let me show you an example:

Bart posted a modified example of my code.  In it he used memset this way:

#define N_LETTERS 26
unsigned char sc[N_LETTERS];
memset(sc, 0, N_LETTERS);

A tutorialspoint.com webpage does it similarly:
char str[50];
memset(str,'$',7);

Should be simple, right?

So I try it in my code, to replace a small loop:

int wsvals[26]={0};   (not a char as in previous examples)
memset(wsvals,0,26);

Doesn't work.  The code compiles (tcc Windows) with no warnings, but it 
doesn't execute.

Finally on stackoverflow I find this:
"Note that for memset you have to pass the number of bytes, not the 
number of elements because this is an old C function:

So I do:  memset(wsvals,0,26 * sizeof(int));

And it works.

Most of the descriptions on the web say memset "is used to fill a block 
of memory with given/particular value."  No mention of the datatype.

Why do I need to also use sizeof() for an int but not a char?

Thread

How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 13:35 -0400
  Re: How to use a struct with qsort()? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-19 10:22 -0700
    Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 14:19 -0400
      Re: How to use a struct with qsort()? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-19 19:36 +0100
      Re: How to use a struct with qsort()? Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-19 18:44 +0000
  Re: How to use a struct with qsort()? Barry Schwarz <schwarzb@delq.com> - 2019-10-19 10:23 -0700
  Re: How to use a struct with qsort()? Ike Naar <ike@sdf.lonestar.org> - 2019-10-19 19:09 +0000
    Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 15:51 -0400
      Re: How to use a struct with qsort()? already5chosen@yahoo.com - 2019-10-19 13:09 -0700
        Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 16:26 -0400
          Re: How to use a struct with qsort()? already5chosen@yahoo.com - 2019-10-19 13:51 -0700
            Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 17:24 -0400
              Re: How to use a struct with qsort()? already5chosen@yahoo.com - 2019-10-19 14:49 -0700
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-19 18:26 -0400
                Re: How to use a struct with qsort()? already5chosen@yahoo.com - 2019-10-19 16:32 -0700
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-20 09:22 -0400
                Re: How to use a struct with qsort()? Paul <nospam@needed.invalid> - 2019-10-26 04:15 -0400
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-26 09:37 -0400
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-26 15:40 +0100
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-28 19:49 -0400
                Re: How to use a struct with qsort()? Paul <nospam@needed.invalid> - 2019-10-29 01:59 -0400
                Re: How to use a struct with qsort()? Paul <nospam@needed.invalid> - 2019-10-30 04:54 -0400
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-30 11:54 +0000
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-30 08:58 -0700
                Re: How to use a struct with qsort()? Öö Tiib <ootiib@hot.ee> - 2019-11-07 01:10 -0800
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-11-07 10:51 +0000
                Re: How to use a struct with qsort()? Paul <nospam@needed.invalid> - 2019-10-26 15:03 -0400
                Re: How to use a struct with qsort()? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 21:50 +0100
                Re: How to use a struct with qsort()? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-04 16:02 -0800
            Re: How to use a struct with qsort()? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-10-21 11:58 +0000
            Re: How to use a struct with qsort()? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-23 04:51 -0700
          Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-19 23:25 +0100
            Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-19 15:38 -0700
              Re: How to use a struct with qsort()? David Brown <david.brown@hesbynett.no> - 2019-10-20 14:44 +0200
              Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-22 15:42 -0400
              Re: How to use a struct with qsort()? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-23 05:47 -0700
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-23 16:40 +0100
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-23 13:51 -0700
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-23 23:07 +0100
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-23 15:50 -0700
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-24 01:20 +0100
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-23 18:20 -0700
                Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-24 10:40 +0100
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-24 11:00 -0700
          Re: How to use a struct with qsort()? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-20 00:30 +0100
            Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-20 00:44 +0100
          Re: How to use a struct with qsort()? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-20 01:27 +0100
          Re: How to use a struct with qsort()? Manfred <noname@add.invalid> - 2019-10-25 20:30 +0200
            Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-25 16:07 -0400
            Re: How to use a struct with qsort()? Ike Naar <ike@sdf.lonestar.org> - 2019-10-26 07:27 +0000
              Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-26 02:11 -0700
            Re: How to use a struct with qsort()? Bart <bc@freeuk.com> - 2019-10-26 11:06 +0100
              Re: How to use a struct with qsort()? Manfred <noname@invalid.add> - 2019-10-26 16:58 +0200
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-26 18:17 -0400
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-26 16:08 -0700
                Re: How to use a struct with qsort()? DFS <nospam@dfs.com> - 2019-10-26 21:33 -0400
                Re: How to use a struct with qsort()? Keith Thompson <kst-u@mib.org> - 2019-10-26 22:10 -0700
                Re: How to use a struct with qsort()? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-27 01:48 +0100
                Re: How to use a struct with qsort()? Manfred <noname@invalid.add> - 2019-10-27 19:29 +0100
                Re: How to use a struct with qsort()? Barry Schwarz <schwarzb4aarp@gmail.com> - 2019-10-27 13:09 -0700

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