LNK2019

unresolved external symbol "public: __thiscall Graph_lib::Menu::Menu(struct Graph_lib::Point,int,int,enum Graph_lib::Menu::Kind,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0Menu@Graph_lib@@QAE@UPoint@1@HHW4Kind@01@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function "public: __thiscall Graph_lib::Lines_window::Lines_window(struct Graph_lib::Point,int,int,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0Lines_window@Graph_lib@@QAE@UPoint@1@HHABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)