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From: Purtill@MIT-MULTICS.ARPA (Mark Purtill)
Newsgroups: net.lang.c
Subject: Re: Style, etc.
Message-ID: <217@brl-tgr.ARPA>
Date: Sat, 27-Jul-85 20:43:00 EDT
Article-I.D.: brl-tgr.217
Posted: Sat Jul 27 20:43:00 1985
Date-Received: Wed, 31-Jul-85 00:57:20 EDT
Sender: news@brl-tgr.ARPA
Lines: 26

<Fnord>

>> while(ptr++->duck)  /* move pointer to the duck after the next NULL */
>>   ;
>This one is even more obscure than the last.  I am a C programmer, and
>this tells me nothing - indeed it is dead wrong, as it simply will not
>happen as the comment might lead me to believe.  This will leave me
>with ptr pointing to the next available record whose element named
>duck is 0.
No, remember that foo++ increments foo *after* it get's the value.  So
after the code fragment above is done, (ptr-1)->duck is 0, and ptr->duck
is what ever it is.  Incidentally, I would write this

          /* skip *past* first some_struct with NULL duck */
          while( (some_struct_ptr++ -> duck) != NULL) ; 

          /* next bit of code */, 

where some_struct is the name of the structure some_struct_ptr (formerly
ptr) points to.  The comment is mostly there because often when I have
fred++, I really mean ++fred, so it's useful to point out (to me,
mostly) that I really know what I'm doing.

       Mark
^.-.^  Purtill at MIT-MULTICS.ARPA    **Insert favorite disclaimer here**
(("))  2-032 MIT Cambrige MA 02139