Compilare: user.c: In function ‘main’: user.c:10:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("subbit.in","r",stdin); ^ user.c:11:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("subbit.out","w",stdout); ^ user.c:13:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&ch); ^ user.c:24:22: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&ch); ^