Compilare: user.cpp: In member function ‘void automaton::add_word(const string&, int)’: user.cpp:44:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++){ ^ user.cpp: In member function ‘void automaton::build_fails()’: user.cpp:69:67: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(k && !states[k].transitions[states[y].letter]) ^ user.cpp:72:58: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(states[k].transitions[states[y].letter]) ^ user.cpp:73:61: warning: array subscript has type ‘char’ [-Wchar-subscripts] k=states[k].transitions[states[y].letter]; ^ user.cpp: In member function ‘void automaton::run_automaton(const string&)’: user.cpp:95:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<s.size();i++){ ^