Sylvain Pion wrote:
On Sat, Dec 11, 2004 at 12:38:27AM -0500, David Abrahams wrote:
Okay, I buy it.
You forgot that you already bought it 18 months ago :)
See the thread starting at : http://lists.boost.org/MailArchives/boost/msg47144.php
Probably a note in the documentation concerning this "non-intuitive" fact would help.
Probably a simple fix to the library would help more.
Another note : filter_iterator's complexity may not match the requirements of iterators (increment in constant time amortized), depending on the predicate's behavior.
That's a tricky question, which is why it's been left unanswered. You might look at it this way: for any filter and sequence of length N there are some constant number of elements M that will pass the filter. If the cost of traversing the unfiltered sequence is O(N) then so is the cost of traversing the filtered sequence. But N/M is a constant, so it's also N/M O(M) and therefore also O(M). Is that stretching the definition of an iterator? I'm not sure. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com