Compilare: user.cpp: In member function ‘void automaton::add_word(const string&, int)’: user.cpp:46:30: 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:71:67: warning: array subscript has type ‘char’ [-Wchar-subscripts] while(k && !states[k].transitions[states[y].letter]) ^ user.cpp:74:58: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(states[k].transitions[states[y].letter]) ^ user.cpp:75:61: 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:91:30: 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::calc_final()’: user.cpp:104:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<states.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:153:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<x.states.size();i++){ ^