foo.cc: In member function ‘void BigNumber::Div(const BigNumber&)’:
foo.cc:153:51: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<unsigned int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
  153 |                                 for (int i = 0; i < rlist.size(); i++) {
      |                                                 ~~^~~~~~~~~~~~~~
foo.cc: In function ‘std::ostream& operator<<(std::ostream&, const BigNumber&)’:
foo.cc:209:33: warning: array subscript has type ‘char’ [-Wchar-subscripts]
  209 |                 out << b16[n.N[i]];
      |                            ~~~~~^