/in/foo.cc: In function 'char judge(std::__cxx11::string)':
/in/foo.cc:26:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i<str.size();i++){
                ~^~~~~~~~~~~
/in/foo.cc:34:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^