Compilare: user.cpp: In function ‘int main()’: user.cpp:44:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < prime.size () && prime[i] <= B; i ++) ^ user.cpp:38:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("difprim.in", "r", stdin); ^ user.cpp:39:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("difprim.out", "w", stdout); ^ user.cpp:41:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &A, &B); ^