/in/foo.cc: In member function 'BigInteger BigInteger::operator+(const BigInteger&) const':
/in/foo.cc:36:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if(g == 0 && i >= s.size() && i >= b.s.size()) break;
                    ~~^~~~~~~~~~~
/in/foo.cc:36:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if(g == 0 && i >= s.size() && i >= b.s.size()) break;
                                     ~~^~~~~~~~~~~~~
/in/foo.cc:38:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if(i < s.size()) x += s[i];
          ~~^~~~~~~~~~
/in/foo.cc:39:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if(i < b.s.size()) x += b.s[i];
          ~~^~~~~~~~~~~~
/in/foo.cc: In function 'std::ostream& operator<<(std::ostream&, const BigInteger&)':
/in/foo.cc:52:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j = 0; j < strlen(buf); j++) out << buf[j];
                    ~~^~~~~~~~~~~~~