Compilare: user.cpp: In function ‘int main()’: user.cpp:74:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ubercool.in","r",stdin); ^ user.cpp:75:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ubercool.out","w",stdout); ^ user.cpp:77:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&Q); ^ user.cpp:84:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&X); ^ user.cpp: In function ‘bool isprim(long long int)’: user.cpp:53:19: warning: ‘i’ is used uninitialized in this function [-Wuninitialized] while (prime[i]<=R && i<=prime[0]) ^