Compilare: user.cpp: In function ‘int main()’: user.cpp:34:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < d[1].size(); i++) ^ user.cpp:52:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < d[y].size(); i++) ^ user.cpp:60:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < r.size(); i++) ^