Path: csiph.com!eternal-september.org!feeder.eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c,comp.programming
Subject: Re: C is not a low level language
Date: Wed, 27 Feb 2019 22:37:49 -0800
Organization: None to speak of
Lines: 56
Message-ID: <ln1s3so1tu.fsf@kst-u.example.com>
References: <q4sc7g$bjg$1@dont-email.me> <q4t5ht$ol3$2@toylet.eternal-september.org> <q4t78c$ver$1@toylet.eternal-september.org> <qsf47edk21e705cfp6kj73b4fa5hbqjf59@4ax.com> <20190224075627.3004ea1cebad8b4055574d17@eircom.net> <7qm47e99prt8o5ga9phi6mofn72ek248i2@4ax.com> <q4tsnm$452$1@dont-email.me> <q4u7f1$2an$1@dont-email.me> <60mckf-teg.ln1@gangtai.home.grep.be> <YvvWcMx6b8ccFwKI@255soft.uk> <q50n3i$gvu$2@dont-email.me> <20190225142618.6663a9845e7fe4eb9c60ad89@eircom.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: reader02.eternal-september.org; posting-host="740125203046c87687fac1b57b8ff8cc"; logging-data="26815"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/95ax40fC1shUAz292aojb"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux)
Cancel-Lock: sha1:SaV3HZq8iza+5FqFrOlCrARB1sU= sha1:lgOvdqznC9WPJ+m3E8CooH7GnZY=
Xref: csiph.com comp.lang.c:141488 comp.programming:9797

[Dropped extraneous newsgroups]
Ahem A Rivet's Shot <steveo@eircom.net> writes:
> On Mon, 25 Feb 2019 12:29:38 +0000
> Richard Heathfield <rjh@cpax.org.uk> wrote:
>
>> Which is the saving grace of Piet. Piet programs can be rather attractive.
>
> 	This program is pretty ...
>
> #define _ -F<00||--F-OO--;
> int F=00,OO=00;main(){F_OO();printf("%1.3f\n",4.*-F/OO/OO);}F_OO()
> {
>             _-_-_-_
>        _-_-_-_-_-_-_-_-_
>     _-_-_-_-_-_-_-_-_-_-_-_
>   _-_-_-_-_-_-_-_-_-_-_-_-_-_
>  _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
>  _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
>  _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
>  _-_-_-_-_-_-_-_-_-_-_-_-_-_-_
>   _-_-_-_-_-_-_-_-_-_-_-_-_-_
>     _-_-_-_-_-_-_-_-_-_-_-_
>         _-_-_-_-_-_-_-_
>             _-_-_-_
> }
>
>
> 	... but far from readable.

That program is from the 1989 IOCCC (International Obfuscated C Code
Contest).  It doesn't produce the expected result because it makes an
assumption about the behavior of the C preprocessor.

Changing the #define line to

#define _ F-->00||F-OO--;

fixes the problem.  (It still produces some warnings, and strictly
speaking has undefined behavior, fixable by updating adding an #include
directive and updating the function declarations.)

With this change, the output is

    3.141

https://ioccc.org/1988/westley.c
https://ioccc.org/1988/westley.hint

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */