/in/foo.cc: In function 'void Sepr(std::__cxx11::string, std::__cxx11::string&, std::__cxx11::string&, std::__cxx11::string&)':
/in/foo.cc:120:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i = 0; i < s.length(); i++) {
             ~~^~~~~~~~~~~~
/in/foo.cc:127:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(i < s.length()) a += s[i++];
         ~~^~~~~~~~~~~~
/in/foo.cc:134:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(i < s.length()) b += s[i++];
         ~~^~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:141:9: warning: unused variable 'line' [-Wunused-variable]
     int line = 0;
         ^~~~