Compilare: user.c: In function ‘main’: user.c:15:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("scmax.in", "r", stdin); ^ user.c:16:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("scmax.out", "w", stdout); ^ user.c:20:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:22:8: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &v[i]); ^ user.c: In function ‘ins’: user.c:57:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘copy’: user.c:67:1: warning: control reaches end of non-void function [-Wreturn-type] } ^