/in/foo.cc: In function 'std::__cxx11::string stringDivString(std::__cxx11::string, std::__cxx11::string)':
/in/foo.cc:100:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < a.length(); i++)
                  ~~^~~~~~~~~~~~
/in/foo.cc: In function 'std::__cxx11::string stringModString(std::__cxx11::string, std::__cxx11::string)':
/in/foo.cc:121:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < a.length(); i++)
                  ~~^~~~~~~~~~~~