Path: utzoo!attcan!uunet!mcvax!hp4nl!orcenl!bengsig From: bengsig@oracle.nl (Bjorn Engsig) Newsgroups: comp.lang.c Subject: Re: When is a cast not a cast? Message-ID: <337.nlhp3@oracle.nl> Date: 22 May 89 12:06:45 GMT References: <406@skye.ed.ac.uk> <10276@smoke.BRL.MIL> <2890@buengc.BU.EDU> <334.nlhp3@oracle.nl> <2918@buengc.BU.EDU> Reply-To: bengsig@oracle.nl (Bjorn Engsig) Organization: ORACLE Europe, The Netherlands Lines: 32 In article <334.nlhp3@oracle.nl> I wrote: >>BTW, what is the sum of the two 'pointers' earth *russia, *southamerica : >>58 45' 22" north, 43 45' 45" east >>and >>23 47' 19" south, 95 13' 18" west > and in article <2918@buengc.BU.EDU> bph@buengc.bu.edu (Blair P. Houghton) replied: >what is the sum of >23 47' 19" south, 43 45' 45" east >and >4 Blair, you are totally missing my point here. I used a geometric example to show the nonsense in adding two pointers, and as I also pointed out in that article, the difference between two pointers is very well defined; in this case, however, it is not a plain number but a direction and a distance, e.g. 27 degrees, 350 km. Your supposed counter example of adding a geometric pointer and a number is of course invalid, since you are not adding a pointer difference (direction, distance) to a pointer. Exactly the same was pointed out by Karl Heuer in article <13189@haddock.ima.isc.com>, using points in the plane [a pointer] and vectors [a point(er) difference]. So please try to understand that adding two pointers does not yield anything meaningful. Let's close down the subject, there shouldn't be any more debate. -- Bjorn Engsig, ORACLE Europe \ / "Hofstadter's Law: It always takes Path: mcvax!orcenl!bengsig X longer than you expect, even if you Domain: bengsig@oracle.nl / \ take into account Hofstadter's Law"