foo.cc: In member function 'void BigIntArray::Sort()':
foo.cc:137:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<BigInt>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  137 |       for (int i = 1; i < A.size(); i++)
      |                       ~~^~~~~~~~~~
foo.cc: In member function 'void BigIntArray::print()':
foo.cc:148:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<BigInt>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  148 |   for (int i = 0; i < A.size(); i++)
      |                   ~~^~~~~~~~~~
foo.cc: In function 'bool operator<(const BigInt&, const BigInt&)':
foo.cc:89:2: warning: control reaches end of non-void function [-Wreturn-type]
   89 |  }
      |  ^

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