difference among Sequences container: vector, deque, list
difference among associate container: set, map, hash
difference among smart pointer: std::unique_ptr, std::shared_ptr, std::weak_ptr
difference between struct and class
read C++ code and give result: related to virtual function and template
Shell and Python questions: awk print column, Python dictionary
Use C++ to realize a class: understand map, pair, struct, operator overload, class