Path: utzoo!mnetor!uunet!husc6!mit-eddie!uw-beaver!cornell!rochester!PT.CS.CMU.EDU!andrew.cmu.edu!jv0l+
From: jv0l+@andrew.cmu.edu (Justin Chris Vallon)
Newsgroups: comp.sys.mac
Subject: Re: How Doy you get a real random number in LSC?
Message-ID: <0WD9Zey00Xo7sDQ0Cl@andrew.cmu.edu>
Date: 15 Mar 88 02:39:38 GMT
Organization: Carnegie Mellon University
Lines: 19
In-Reply-To: <7671@cisunx.UUCP>


jasst3@cisunx.UUCP (Jeffry A. Sullivan) asks:
>>
How do you get a real random number in LSC?  I have tried using rand() and
Random() (from math lib and quickdraw, repectively).  They both give the same
sequence of numbers each time at startup.  I am trying to write a randomizer
INIT that works on a mac II, but the randomness is all that's holding me back.
(I think...)
<<

The QD function Random() uses the global variable RandSeed, which is always
initialized to the same number when you call InitGraf(&thePort).  To change the
sequence of random numbers, you must initialize the seed.  A seed that I use a
lot is either the current system time, since it will never be the same for two
instances of your initialization.  Look for the function which returns the
number of seconds elapsed since 1/1/04.  Use this number (ANDed w/0xffff) to
generate a unique random number seed.

-Justin
justin.vallon@andrew.cmu.edu