Compilare: user.cpp: In function ‘int main()’: user.cpp:48:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < VPOS.size(); ++i) g << VPOS[i].second << '\n'; ^ user.cpp:49:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < VNEG.size(); ++i) g << VNEG[i].second << '\n'; ^