Path: utzoo!attcan!uunet!crdgw1!antarctica!davidsen
From: davidsen@antarctica.crd.GE.COM (william E Davidsen)
Newsgroups: comp.lang.c
Subject: Re: count of bits set in a long
Keywords: bits set, count of, long
Message-ID: <12330@crdgw1.crd.ge.com>
Date: 2 Oct 90 14:00:57 GMT
References: <37545@ut-emx.uucp> <1990Sep26.180240.11516@everexn.com>
Sender: news@crdgw1.crd.ge.com
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Organization: GE Corporate R&D Center, Schenectady NY
Lines: 22


  There have been lots of fast but non-portable solutions posted. I
think this problem lends itself to a non-portable solution for speed,
but please remember that if you assume (a) all longs have 32 bits or (b)
all computers have 2's complement arithmetic, or (c) all bytes are 8
bits...

                ** All the world's not a VAX (or Sun) **

and many of the solutions posted are not going to work.

  I like the one which said (paraphrase)

	while (n) {
	  count += (n & 1);
	  n >>= 1;
	}
-- 
Bill Davidsen (davidsen@crdos1.crd.ge.com, uunet!crdgw1!crdos1!davidsen)
  GE Corp R&D Center, Schenectady NY
  Moderator of comp.binaries.ibm.pc and 386users mailing list
       "This is your PC. This is your PC on OS/2. Any questions?"