how to iterate in reverse over a map in c++

Question

I'm having trouble iterating in reverse over a map in gcc c++. When I use a reverse iterator, it seems I can't assign anything to it - the compiler complains. I'm working around it with some awkward code using a forward iterator, but it's not very elegant. Any thoughts?

Answer 1

You mean something like:

std::map<std::string, std::string> theMap;
/* do stuff */

for (std::map<std::string, std::string>::reverse_iterator iter = theMap.rbegin(); iter != theMap.rend(); ++iter)
{
    /* do more stuff */
}

Does not work? When you say "the compiler complains", we can only guess so much. How does it complain? Error? Warning?

Answer 2

You should check, how you obtain iterator range ( it should be rbegin()/rend() instead begin()/end() ). Do you really use reverse_iterator ( not const_reverse_iterator )?