race.cpp: In member function 'void BigInt::operator+=(const BigInt&)': race.cpp:23: warning: comparison between signed and unsigned integer expressions race.cpp:24: warning: comparison between signed and unsigned integer expressions race.cpp:25: warning: comparison between signed and unsigned integer expressions race.cpp:25: warning: comparison between signed and unsigned integer expressions race.cpp: In function 'std::ostream& operator<<(std::ostream&, const BigInt&)': race.cpp:67: error: 'setfill' was not declared in this scope race.cpp:67: error: 'setw' was not declared in this scope