Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!gatech!hubcap!ncrcae!ncrlnk!uunet!mcvax!ukc!dcl-cs!aber-cs!pcg
From: pcg@aber-cs.UUCP (Piercarlo Grandi)
Newsgroups: comp.lang.c
Subject: Re: Always use braces (was: Suggested new C loop syntax)
Message-ID: <474@aber-cs.UUCP>
Date: 2 Jan 89 17:50:41 GMT
Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
Distribution: eunet,world
Organization: CS Dept., University College of Wales, Aberystwyth, UK
	(Disclaimer: my statements are purely personal)
Lines: 66

In article <11037@ulysses.homer.nj.att.com> cjc@ulysses.homer.nj.att.com (Chris Calabrese[mav]) writes:

#   In article <271@twwells.uucp>, bill@twwells.uucp (T. William Wells) writes:
#   > In article <8@estinc.UUCP> fnf@estinc.UUCP (Fred Fish) writes:
#   > ...
#   > : I was recently helping out a freshman CS major with her C homework and
#   > : found out, to my horror, that the teacher in the course was marking
#   > : off points for code which included braces when they weren't strictly
#   > : required.  They were teaching her to write code like:
#   > :
#   > :       inchar = getchar ();
#   > :       while (inchar != EOF)
#   > :               if (inchar == 0)
#   > :                       goto done;
#   > :               else
#   > :                       inchar = getchar ();
#   > : done: return inchar;
#   > :
#   > : Ickkk!!!
#   > 
#   > Double Ickkkk!!!! A goto where a break would have done.

#   This is yet another tripple icky example of CS professors
#   thinking that just because they can get the example programs
#   in K&R to compile, and because they did work in Fortran in
#   their thesis on astrophysics, they are qualified to teach
#   C (or any other language).  Wrong, wrong, wrong.
#   
#   Any C guru qualified (in my humble opinion) to teach
#   C would be trying to teach code which looks like:
#   

#   	/*
#   	 * assume students have not learned the ',' operator yet
#   	 */
#   	do	{
#   		inchar = getchar();
#   		} while(inchar != EOF && inchar);
#   	return inchar;
#   
#   Personally, I haven't decided whether the while should be lined
#   with the do or the loop body yet, but I like the brace alignment
#   this way.

I would beg to suggest the following for the loop:

    for
    (
	inchar = fgetc(stdin);
	inchar != EOF && inchar != '\0';
	inchar = getc(stdin)
    );

Just to make it evident that this is a sequential scan. I use fgetc(3) to
initialize inchar because it does not get expanded inline (unless of course
I knew that in most cases the loop would be exited immediately)..

The following solution is more compact and arguably more in the C tradition,
but I think that making explicit the iteration structure with a for(;;) and
the explicit test against '\0' are somewhat more readable.

    while ((inchar = getchar()) && inchar != EOF);
-- 
Piercarlo "Peter" Grandi			INET: pcg@cs.aber.ac.uk
Sw.Eng. Group, Dept. of Computer Science	UUCP: ...!mcvax!ukc!aber-cs!pcg
UCW, Penglais, Aberystwyth, WALES SY23 3BZ (UK)