Compilare: user.cpp: In function ‘int main()’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < C.size(); i ++) B.push_back(C[i] - '0'); ^ user.cpp:20:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (b < B.size()) ^ user.cpp:29:57: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = A.size() - 1; i >= 0 && b < B.size(); i --) ^