/in/foo.cc: In function 'std::__cxx11::string enc(std::__cxx11::string, int)':
/in/foo.cc:23:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<s.length(); i++) {
               ~^~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:52:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<text.length(); i++) {
                ~^~~~~~~~~~~~~~
/in/foo.cc:56:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0; i<text.length(); i++) {
                ~^~~~~~~~~~~~~~
/in/foo.cc:63:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<vs.size();i++)
              ~^~~~~~~~~~