Compilare: user.cpp: In function ‘int main()’: user.cpp:36:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < D.size(); ++i) ^ user.cpp:47:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j != D.size()-1) ^ user.cpp:47:11: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (j != D.size()-1) ^