Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!ig!arizona!robert
From: robert@arizona.edu (Robert J. Drabek)
Newsgroups: comp.lang.c
Subject: Re: comma operator
Summary: answer
Message-ID: <13074@megaron.arizona.edu>
Date: 3 Aug 89 16:51:39 GMT
References: <10099@mpx2.mpx.com> <93@microsoft.UUCP> <10100@mpx2.mpx.com> <918@helios.toronto.edu>
Organization: U of Arizona CS Dept, Tucson
Lines: 27

In article <918@helios.toronto.edu>, dooley@helios.toronto.edu (Kevin Dooley) writes:
> 
> Can anybody tell me if there is a usage where the comma is 'better'.
> By this I mean are there any places where using a comma makes the 
> code more readable, efficient, produce cleaner/faster assembler (I
> know this is compiler dependant).  It's just that I've never seen a
> program with the comma operator where I didn't scream and edit it out.

I agree with you.  The one place, though, where it is used is in "for"
loops:  for (i = 0, j = 9; ...; i++, j--)

I have seen the following "attempt" at using a comma operator in a function
call:

       func(expr1, expr2)

The writer thought he was using the comma operator since the function
had been defined as having a single argument.  He did get

       func((expr1, expr2))

to work.  I don't know if all compilers would get this, though.
-- 
Robert J. Drabek
Department of Computer Science
The University of Arizona
Tucson, AZ  85721