OOps At Monday 2004-09-27 01:02, you wrote:
At Sunday 2004-09-26 17:35, you wrote:
Victor A. Wagner Jr. <vawjr@rudbek.com> wrote: The midpoint between them is (this is legal using your constraints):
a + (b-a)/2
1st year algebra teaches us that this is equivalent to:
(a+b)/2
While on most systems the intermediate value (a+b) would be useless, as soon as you divide by 2 it again becomes useful.
with a third pointer (T* c;):
(a+b+c)/3
becomes calculable and useful though clearly
Just a small $0.02...
(a + b) is a dangerous thing in a 32 bit world full of arithmetic overflow opportunities. You'd have to have a very good reason for doing it this way I'd think.
a + (a-b) / 2 is a bit safer
I don't see the safety issue and what you showed is incorrect; a + (b-a) / 2 is at least correct, but b-a overflows just as readily as a+b
I should know better than to try this stuff at 0100 local. Of course (b-a) is less likely to overflow than (a+b). It's certainly fair to presume that the _size_ of any such container will be small in comparison to the range addresses
matt matthurd@acm.org _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
Victor A. Wagner Jr. http://rudbek.com The five most dangerous words in the English language: "There oughta be a law" _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
Victor A. Wagner Jr. http://rudbek.com The five most dangerous words in the English language: "There oughta be a law"