From: demandrd AT compusmart DOT ab DOT ca (Demandred)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Allegro ex11.c
Date: Fri, 13 Feb 1998 00:46:00 GMT
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On Mon, 09 Feb 1998 13:18:12 -0800, Dan <dyoon AT home DOT com> was heard to
ramble:

>i have a question concerning a part of the code from the allegro example
>files.  it's probably a stupid question but i've looked in my c and c++
>books and i can't find the answer.  here's the question, in this small
>snippet of the code..
>
>      hotspot[c] += (random() & 7) - 3;
>
>what does "random() & 7" do?  i'm figuring random() returns a random
># of type int maybe?  but i have no idea what the "& 7" does.  the & 7
>is the only thing that i need an explenation for.  any help would be
>much appreciated.

Hmmm... random() returns a random (duh) integer that can be pretty
huge (0 to MAXINT, IIRC), so I'd guess that the & 7 (bitwise AND with
111b) acts like a % 8 (modulus 8)(??).  Why, I don't know... maybe
bitwise AND is faster than mod?



<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-
<-The Christian Right is Neither<-
<-Sinister Ergo Cogito          <-
<-http://www.geocities.com/     <-
<-  SiliconValley/Peaks/9539/   <-
<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-<-