Hi! Thanks always for all the help. Today I would like to ask about sets and multisets from the STL of C++. If I have a class such as: class Aclass { private: int theKey; float theData; }; ---------------- and I would like to use objects from it in a multiset how can I do it? I read the sintax of MultiSets (and sets too) is multiset<Key, compareF> ---------------- and that for sets of ints or doubles this compareF usually is not neccesary to be specified. But for sets of objects or pointer to objects what else should I do??? I am thinking the following is not enough: typedef std::multiset<Aclass> TsetOfClasses; ---------------- or typedef std::multiset<Aclass *> TPsetOfClasses; ---------------- I read in the documentation that a key comparison function should be provided. Please help me (by the way, I know that in this particular case a Map would be better, but I am interested in using sets because in a method the object has to have access to the key and with maps that is not possible)