Compilare: user.c: In function ‘main’: user.c:15:33: warning: integer overflow in expression [-Woverflow] long long l = 1, r = (1 << 31) - 1; ^ user.c:19:2: warning: format ‘%lld’ expects argument of type ‘long long int *’, but argument 2 has type ‘int *’ [-Wformat=] scanf("%lld", &P); ^ user.c:16:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.in", "r", stdin); ^ user.c:17:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("fact.out", "w", stdout); ^ user.c:19:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &P); ^