Compilare: user.cpp: In function ‘int main()’: user.cpp:15:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (unsigned int i=2;i<=n;i+=2) ^ user.cpp:17:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (unsigned int i=3;i<=n;i+=2) ^ user.cpp:22:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (unsigned int j=1;j<=n;j++) ^