Compilare: user.c: In function ‘read_and_build’: user.c:339:10: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.in", "r", stdin); ^ user.c:343:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", str); ^ user.c:344:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:347:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", word); ^ user.c: In function ‘print’: user.c:357:10: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.out", "w", stdout); ^