Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!wasatch!utah-gr!uplherc!sp7040!obie!wes
From: wes@obie.UUCP (Barnacle Wes)
Newsgroups: comp.lang.c
Subject: Re: Unnecessary Macros (was Re: Unnecessary Parenthesis)
Summary: Sure there's a good way to write it!
Message-ID: <207@obie.UUCP>
Date: 7 Oct 88 02:20:32 GMT
References: <2089@ssc-vax.UUCP> <441@kaon.uchicago.edu> <1401@devsys.oakhill.UUCP> <8590@smoke.ARPA>
Organization: the Well of Souls
Lines: 31

In article <8078@haddock.ima.isc.com> karl@haddock.ima.isc.com (Karl Heuer) writes:
> 	z = square(*p++) + square(getchar());
> I dislike the original macro, but the fact remains that there is no good way
> to write this in C.

In article <8590@smoke.ARPA>, gwyn@smoke.ARPA (Doug Gwyn ) replies:
| One wonders whether this is much of a problem.
| (Note that the example is silly.)
| 
| There have been many occasions when I've needed the sum of two squares,
| but I've never felt the need for the ability to define a "square" macro
| in order to compute that.

This code fragment was taken from a function that calculates the true
wind speed and heading based on the apparent wind speed and angle, and
the speed and course of a sailboat.  Note the last line:

       /*
	* Now return the true wind vector to normal coordinates.
	*/
	tw.heading = atan2(tw.ycomp, tw.xcomp);
	tw.speed = sqrt((tw.ycomp * tw.ycomp) + (tw.xcomp * tw.xcomp));

This seems the obvious way to perform such a calculation to me.  If
any of you net.c.programmers really can't stand this style, please tell
me why!
-- 
                     {hpda, uwmcsd1}!sp7040!obie!wes

         "How do you make the boat go when there's no wind?"
                                 -- Me --