Compilare: user.cpp: In function ‘int main()’: user.cpp:376:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<sir.size();i++) ^ user.cpp: In instantiation of ‘char* list<Ttype>::show_list_reversed() [with Ttype = int]’: user.cpp:363:6: required from ‘void stack<Ttype>::show_stack_reversed(std::ofstream&) [with Ttype = int; std::ofstream = std::basic_ofstream<char>]’ user.cpp:381:24: required from here user.cpp:216:19: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] afisare[i]=NULL; ^ user.cpp: In member function ‘char* list<Ttype>::show_list_reversed() [with Ttype = int]’: user.cpp:221:1: warning: control reaches end of non-void function [-Wreturn-type] } ^