I have committed a new algorithm named "gather" into Boost.Algorithm. Actually, it's one I wrote for Sean Parent as part of ASL about five years ago, and it's the first (of hopefully many) of the bits oF ASL to be moved into boost. Here's a summary: gather() takes a collection of elements defined by a pair of iterators and moves the ones satisfying a predicate to them to a position (called the pivot) within the sequence. The algorithm is stable. The result is a pair of iterators that contains the items that satisfy the predicate. template <typename ForwardIterator, typename Pred> std::pair<ForwardIterator,ForwardIterator> gather ( ForwardIterator first, ForwardIterator last, ForwardIterator pivot, Pred pred ); Given an sequence containing: int [] arr = { 0 1 2 3 4 5 6 7 8 9 }; A call to gather ( arr, arr + 10, arr + 4, IsEven) will result in: 1 3 0 2 4 6 8 5 7 9 |---|-----| first | second pivot where first and second are the fields of the pair returned by the call. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki