Compilare: user.cpp: In function ‘int main()’: user.cpp:18:36: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘int’ [-Wformat=] printf("%lld\n", 2*x*ans[x]); ^ user.cpp:8:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.in", "r", stdin); ^ user.cpp:9:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum.out", "w", stdout); ^ user.cpp:10:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int n, i, x; scanf("%d", &n); ^ user.cpp:17:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^