Compilare: user.cpp: In function ‘std::__cxx11::string parse(std::__cxx11::string)’: user.cpp:11:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<e.size()-1;i++) ~^~~~~~~~~~~ user.cpp: In function ‘bool check(std::__cxx11::string)’: user.cpp:25:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<e.size();i++) ~^~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:53:18: warning: operation on ‘T’ may be undefined [-Wsequence-point] int T=(f>>T,T++); ~^~