Compilare: user.cpp: In member function ‘void BigNumber::operator-=(const BigNumber&)’: user.cpp:83:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < that.v.size(); ++i) ^ user.cpp: In member function ‘void BigNumber::operator+=(const BigNumber&)’: user.cpp:101:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); ++i) ^ user.cpp:103:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] v[i] = v[i] + t + (i < that.v.size() ? that.v[i] : 0); ^ user.cpp: In function ‘int main()’: user.cpp:180:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < pos.size(); ++i) ^