/in/foo.cc: In function 'void td(std::__cxx11::string, std::__cxx11::string)':
/in/foo.cc:7:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<t.length();i++)
             ~^~~~~~~~~~~
/in/foo.cc:22:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(i=0;i<t.length();i++)
             ~^~~~~~~~~~~