Compilare: user.cpp: In function ‘int main()’: user.cpp:58:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("farey.in","r",stdin); ^ user.cpp:59:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("farey.out","w",stdout); ^ user.cpp:61:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld %ld",&n,&k); ^