foo.cc: In member function 'BigInt BigInt::operator+(const BigInt&) const':
foo.cc:24:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         while (i < digits.size() || j < other.digits.size()) {
      |                ~~^~~~~~~~~~~~~~~
foo.cc:24:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         while (i < digits.size() || j < other.digits.size()) {
      |                                     ~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:26:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |             if (i < digits.size()) {
      |                 ~~^~~~~~~~~~~~~~~
foo.cc:30:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |             if (j < other.digits.size()) {
      |                 ~~^~~~~~~~~~~~~~~~~~~~~
foo.cc: In member function 'BigInt BigInt::operator*(const BigInt&) const':
foo.cc:45:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |         for (int i = 0; i < digits.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~~
foo.cc:47:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |             for (int j = 0; j < other.digits.size(); j++) {
      |                             ~~^~~~~~~~~~~~~~~~~~~~~

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