Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!spool.mu.edu!uunet!sugar!peterc
From: peterc@Sugar.NeoSoft.com (Peter Creath)
Newsgroups: comp.sys.mac.programmer
Subject: Re: MPW and Think
Summary: I'm going inSANE with Think C!  (HELP! I can't do sines!)
Message-ID: <1991Jun29.165143.12263@Sugar.NeoSoft.com>
Date: 29 Jun 91 16:51:43 GMT
Article-I.D.: Sugar.1991Jun29.165143.12263
References: <1991Jun25.180736.28590@gn.ecn.purdue.edu> <1991Jun29.075457.28418@metro.ucc.su.OZ.AU>
Organization: Sugar Land Unix -- Houston, TX
Lines: 23

OK, folks, how the HELL do I calculate a sine from Think C?  I have tried
using FracSin, but Think C doesn't seem to know how to handle Fract's and
Fixed's.  I can declare them just fine, but when I try something like
defining a Fixed=0.05*(x^2+y^2); and I should be getting 9.25 (I checked
on my calculator), Think C puts what it thinks is 9 into the Fixed.  Upon
examining the exact hex data, Think C isn't converting it to a Fixed.
It's converting it to a long.  So, when I go to FracSin and Think C tries
to put .471.... into a Fract, my debugger says it's 85-thousand something.
Of course, when sines should be from -1 to 1, that does sorta screw up
any calculations you were doing...
 
So is there any way to tell Think C how to handle Fract's and Fixed's?
Or is there an easier way to calculate a sine?  (I've got an SE/30, so
I've got the 68881)
 
PLEASE respond in E-mail.  My news system doesn't allow threading...
--
peterc@sugar.neosoft.com           "Listen, there's a hell of a good
peterc@sugar.hackercorp.com         universe next door.  Let's go!"
(take your pick)                                      -e e cummings


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