Compilare: main.cpp: In member function 'void BigInt::add(BigInt&)': main.cpp:36:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (digits.size() < i + 1) { ~~~~~~~~~~~~~~^~~~~~~ main.cpp:40:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] int otherDigit = i < other.digits.size() ? other.digits[i] : 0; ~~^~~~~~~~~~~~~~~~~~~~~ main.cpp:48:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (digits.size() < size + 1) { ~~~~~~~~~~~~~~^~~~~~~~~~