Wanna talk about... std::set?
Recently I find lack of lessons about STL in the c++. Container std::set is an associative container and header that need to be include for it is, #include <set>; std::set is an associative container that contains a sorted set of unique objects of type Key. Basic example: https://code.sololearn.com/cott0N65Ga0c/#cpp So let's share our tries with member functions in the comments, discuss issues and suggest solutions. As for me most relevante reference is: http://www.cplusplus.com/reference/set/set