Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Is an argument to break, continue a bad idea?
Message-ID: <1990May4.165746.15724@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1990Apr25.180007.13243@cunixf.cc.columbia.edu> <591@atcmpe.atcmp.nl> <738@mwtech.UUCP> <1990Apr30.165059.1839@utzoo.uucp> <742@mwtech.UUCP>
Date: Fri, 4 May 90 16:57:46 GMT

[Puzzled comp.lang.c readers, note that this has moved over from comp.std.c.]

In article <742@mwtech.UUCP> martin@mwtech.UUCP (Martin Weitzel) writes:
>	..... {
>		..... {
>			..... {
>				/*
>				Here we are in some complicated nested
>				conditions and loops. Suddenly something
>				very ugly happens...

Diagnosis:  excessively nested control structures.  The remedy is to re-read
K&R1 chapter 4 about the most important control structure of all:  functions.

In 15 years of active C programming, I don't think I have ever used a goto
in original code.  (Once or twice I have used one in maintaining code that
was already full of them, when I didn't have time to redo it.)  I attribute
this mostly to a strong distaste for deep nesting.  Breaking things up into
functions makes life easier in a lot of ways, not least of them being the
ability to use `return' to get yourself out of messes.  Amazingly enough,
when you do this systematically, you find that you seldom have any desire
to use `goto'.  It just isn't needed.

>>... When you see "goto", you don't know where it goes without
>>hunting for the label, and you don't know if anything else goes to that
>>label without searching the whole function for more gotos...
>
>Really?
>What is your argument? If you wanted to say that `break' is preferable
>over `goto', you must have a *very* advanced syntax directed editor.
>With a normal editor (like "vi"), I'll have less problems to hunt for
>`goto's (with labels!) than for `break'...

I don't care much for `break' either, although I concede its necessity
in some cases because C lacks higher-level constructs to do certain jobs.
Mind tend to come with comments like `/* NOTE BREAK OUT */' to make them
more conspicuous.

>If you recommend to avoid
>`break' too, then what about the additional flags for breaking
>out of loops. Don't they suffers from the same problems(%)? ...

I recommend composing programs in an orderly way to avoid the need, mostly.

>... IMHO flags often obscure
>things that would be clarified by DISCIPLINED USE OF `goto's. 

Yes, it's better to simply avoid both.
-- 
If OSI is the answer, what is |     Henry Spencer at U of Toronto Zoology
the question?? -Rolf Nordhagen| uunet!attcan!utzoo!henry henry@zoo.toronto.edu