On Fri, 8 May 2009, Steven Ross wrote:
If not, is there an alternative way to sort one sequence while swapping
elements in another in a corresponding way? I am not able to join the two input sequences into a single sequence of pairs because of other factors in the use case for this code. Thank you for your help.
std::sort requires a Random Access Iterator. zip_iterator is not a Random Access Iterator.
I've proposed a sorting library here; it only works for Random Access Iterators, but there were some requests in the past for a more general sort implementation. Theoretically, anything that can be iterated and swapped can be sorted. Do you have a genuine usage case where a sort would be useful where an item can be iterated and swapped, but does not have a Random Access Iterator? If so, I could reconsider the request and see if I can find (or write) an effective algorithm and template it.
Yes, I do -- the case of sorting two (or more) corresponding sequences using a zip_iterator. This capability is important to save memory when explicitly zipping the sequences into a new sequence is not possible. Note that zip_iterator still has random access in constant time, but just does not return an actual reference but a tuple of references. -- Jeremiah Willcock