Compilare: user.cpp: In function ‘int main()’: user.cpp:10:32: warning: unused variable ‘j’ [-Wunused-variable] register long long n , i , j , k ; ^ 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 ( 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 ( out , "w" , stdout ) ; ^ user.cpp:12:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%lld" , &n ) ; ^ user.cpp:15:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%d" , &v[i] ) ; ^