Compilare: user.cpp: In function ‘int main()’: user.cpp:18:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < a.size(); ++ i){ ^ user.cpp:27:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.size(); ++i){ ^ user.cpp:30:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(q == a.size()-1){ ^