Compilare: user.cpp: In function ‘void to_big(long long int*, long long int)’: user.cpp:40:15: warning: unused variable ‘k’ [-Wunused-variable] long long k = val; A[0] = 0; ^ user.cpp: In function ‘int main()’: user.cpp:50:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("algebra2.in", "r", stdin); ^ user.cpp:51:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("algebra2.out", "w", stdout); ^ user.cpp:52:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &N); ^