/in/foo.cc: In member function 'bign bign::operator=(const char*)':
/in/foo.cc:88:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 1; i < strlen(num); i++)
                         ~~^~~~~~~~~~~~~
/in/foo.cc:92:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < strlen(a); i++)
                     ~~^~~~~~~~~~~