Compilare: user.cpp: In function ‘int Compare(const Mask&, const Mask&)’: user.cpp:39:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (a.digits[digit] != b.digits[digit]) ^ user.cpp: In function ‘Mask Compute(int)’: user.cpp:75:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < digits.size(); i++, power10 *= 10) { ^