Hello, I tried to use boost::zip_iterator to sort 2 parallel arrays. Unfortunatly gcc does not compile the appended example because it can not convert boost::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::random_access_traversal_tag> to either std::bidirectional_iterator_tag or std::random_access_iterator_tag. Thus it cannot dispatch the correct stl::__copy_backward() procedure. Is sort() not yet supported? mfg Gunter PS: please CC your replies to my eMail. 8<-----------part of error log--------------- /usr/include/c++/3.3/bits/stl_algobase.h: In static member function `static _BidirectionalIter2 std::__copy_backward_dispatch<_BidirectionalIter1, _BidirectionalIter2, _BoolType>::copy(_BidirectionalIter1, _BidirectionalIter1, _BidirectionalIter2) [with _BidirectionalIter1 = boost::zip_iterator<boost::tuples::tuple<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, __gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >, _BidirectionalIter2 = boost::zip_iterator<boost::tuples::tuple<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, __gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >, _BoolType = __false_type]': [...] /usr/include/c++/3.3/bits/stl_algobase.h:392: error: no matching function for call to `__copy_backward( boost::zip_iterator<...>&, boost::zip_iterator<...>&, boost::detail::iterator_category_with_traversal<std::input_iterator_tag, boost::random_access_traversal_tag>)' /usr/include/c++/3.3/bits/stl_algobase.h:360: error: candidates are: _BidirectionalIter2 std::__copy_backward(_BidirectionalIter1, _BidirectionalIter1, _BidirectionalIter2, std::bidirectional_iterator_tag) /usr/include/c++/3.3/bits/stl_algobase.h:371: error: _BidirectionalIter std::__copy_backward(_RandomAccessIter, _RandomAccessIter, _BidirectionalIter, std::random_access_iterator_tag) 8<-----------zip_iter.cpp------------ // sort 2 parallel arrays #include <boost/iterator.hpp> #include <boost/iterator/zip_iterator.hpp> #include <boost/tuple/tuple.hpp> #include <boost/tuple/tuple_comparison.hpp> #include <vector> #include <iostream> int main(int argc, char *argv[]) { typedef std::vector<int> VEC; typedef boost::zip_iterator< boost::tuple<VEC::iterator, VEC::iterator> > zip_iter; VEC v1(10); VEC v2(10); zip_iter iter( boost::make_tuple(v1.begin(), v2.begin()) ); zip_iter iter_end( boost::make_tuple(v1.end(), v2.end()) ); std::sort(iter, iter_end); return EXIT_SUCCESS; }