Compilare: user.cpp: In instantiation of ‘element<t_key, t_info>* list<t_key, t_info>::search_by_key(t_key) [with t_key = int; t_info = std::basic_string<char>]’: user.cpp:136:27: required from ‘void list<t_key, t_info>::addElement(t_key, t_info) [with t_key = int; t_info = std::basic_string<char>]’ user.cpp:203:2: required from ‘void Mymap<t_key, t_info>::push_back(t_key, t_info) [with t_key = int; t_info = std::basic_string<char>]’ user.cpp:61:30: required from here user.cpp:109:18: warning: variable ‘prev’ set but not used [-Wunused-but-set-variable] element<types>* prev = head; ^