Compilare: main.cpp: In function 'void parseString(std::__cxx11::string&)': main.cpp:17:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < s.size();++i){ ~~^~~~~~~~~~ main.cpp: In function 'bool factor()': main.cpp:122:17: warning: array subscript has type 'char' [-Wchar-subscripts] r = map[s[i]]; ^ main.cpp: In function 'int main()': main.cpp:142:14: warning: array subscript has type 'char' [-Wchar-subscripts] map[c] = 1 - map[c]; ^ main.cpp:142:27: warning: array subscript has type 'char' [-Wchar-subscripts] map[c] = 1 - map[c]; ^