Ok, now I want to make find() and erase() methods. In std::map, they return an iterator. Should I wrap the methods find() and erase(), to pass a const K& key, and return a container1:: const_iterator. is it right?
std::map::find and std::map::erase have several overloads: http://www.cplusplus.com/reference/stl/map/find/ http://www.cplusplus.com/reference/stl/map/erase/ And none of erase() overloads returns iterator. By the way, why don't you just inherit from multi_index_container and add [] operator? MIC itself already has STL-complient interace, so trying to rewrite it is hardly worth the effort. The following is your code, but with inheritance: #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/random_access_index.hpp> using namespace boost::multi_index; template<typename K,typename V> struct mutable_pair { typedef K first_type; typedef V second_type; mutable_pair():first(K()),second(V()){} mutable_pair(const K& f,const V&s):first(f),second(s){} mutable_pair(const std::pair<K,V>& p):first(p.first),second(p.second){} K first; mutable V second; }; template<typename K,typename V> class Ordered_Map : public multi_index_container< mutable_pair<K, V>, indexed_by< random_access<>, ordered_unique<member<mutable_pair<K,V>, K, &mutable_pair<K, V>::first> > >
{ public: V& operator[]( const K& key ) { insert(end(), mutable_pair<K, V>(key,V())); return get<1>().find(key)->second; } }; int main() { Ordered_Map<std::string,int> myMap; myMap["Joe"] = 3; myMap["Lillo"] = 9; myMap["Mary"] = -3; for (auto i = myMap.cbegin(); i != myMap.cend(); ++i) std::cout << i->first << " - " << i->second << std::endl; std::cin.get(); return 0; }