...

if it was possible it would allow us to write, for example:

copy( make_filter_iterator(numbers, numbers + N), numbers + N, ostream_iterator<int>(cout, " "));

rather than:

copy( make_filter_iterator(numbers, numbers + N), make_filter_iterator(numbers + N, numbers + N), ostream_iterator<int>(cout, " "));

of course i am aware that i might be missing something obvious ...

I think you are. the signature of std::copy is:

template OutputIterator copy( InputIterator first, InputIterator last, OutputIterator result);

What will the compiler deduce InputIterator to be?

you are right of course - which is a shame. for my own use, however, i would happily rewrite the stl algorithms to allow for this usage. i often find i have issues with that area of the standard library in any case: why does binary_search not return an iterator to the item i'm searching for? why min_element, max_element when best_element, worst_element is less confusing? why no copy_if? etc. of course that could just be me :) ian whittley

At Friday 2004-04-16 12:18, you wrote:

...

From: "Victor A. Wagner Jr."

...

what the heck are best_element and worst_element? at least I _know_ what min and max are.

we all _know_ what min and max are - that's the problem - we have a default predicate in mind - so min_element(begin, end, greater) doesn't work as you would initially (intuitively) expect - to understand it generally requires viewing it as min_indexed_element_if_ordered_by.

you have actually seen someone (other than yourself) write: min_element(begin, end, greater) ?? reminds me of the long gone (thankfully) unless(blah) from BCPL

best and worst have the advantage of requiring a context before they can be understood - best_element(begin, end, greater) should therefore be clear to just about anybody (i would hope :)

ian whittley

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Victor A. Wagner Jr. http://rudbek.com The five most dangerous words in the English language: "There oughta be a law"