Compilare: user.cpp: In function ‘int main()’: user.cpp:86:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); i++) ^ user.cpp:89:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size() - 1; i++) ^ user.cpp:92:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = int(a.size() - 1); i < b.size(); i++) ^