Question

If i have a stl map from string to int and i want to print all the int values sorted – how can i do that?

Answer 1

You cannot sort a map by its values due to the implementation of the map.

If you want to emit the elements in the map in such a sorted order then you have to first dump the map contents into a vector (say) and sort that vector:

template <typename T1, typename T2>
struct less_second {
    typedef pair<T1, T2> type;
    bool operator ()(type const& a, type const& b) const {
        return a.second < b.second;
    }
};

map<string, int> mymap;
// …

vector<pair<string, int> > mapcopy(mymap.begin(), mymap.end());
sort(mapcopy.begin(), mapcopy.end(), less_second<string, int>());

Or alternatively, just copy the values from the map, leaving the keys, and sort the resulting vector directly.