Compilare: user.c: In function ‘p’: user.c:17:15: warning: operation on ‘l’ may be undefined [-Wsequence-point] return (l = p(a, b >> 1)) * l * ((b & 1) ? a : 1); ^ user.c: In function ‘main’: user.c:50:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbint.in", "r", stdin); ^ user.c:51:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbint.out", "w", stdout); ^ user.c:53:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld", &n, &m); ^ user.c:57:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld", &H[N + i]); ^ user.c:62:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld %ld", &op, &a, &b); ^