Compilare: user.cpp: In function ‘int main()’: user.cpp:44:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = A.size() + 1; i < z.size(); ++i) ^ user.cpp:45:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (z[i] == A.size()) ^