Compilare: user.cpp: In function ‘int main()’: user.cpp:20:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i <= n; i++) { ^ user.cpp:24:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= n; i++) ^ user.cpp:26:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int d = 2; d <= n; d++) ^ user.cpp:27:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i + d <= n; i++) ^