Compilare: user.cpp: In function ‘void gen(long long int)’: user.cpp:15:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (p<=lim) ^ user.cpp: In function ‘int main()’: user.cpp:28:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("taste.in","r",stdin); ^ user.cpp:29:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("taste.out","w",stdout); ^ user.cpp:30:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&x,&y); ^