Compilare: user.cpp: In function ‘void sol(int)’: user.cpp:30:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<sizeof(P)&&1LL*P[i]*P[i]<=n&&P[i]!=0;i++){ ^ user.cpp: In function ‘int main()’: user.cpp:53:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cmmmc.in", "r", stdin); ^ user.cpp:54:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cmmmc.out", "w", stdout); ^ user.cpp:58:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &n); ^ user.cpp:60:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &x); ^