Compilare: main.cpp: In function 'void pregen(long long int)': main.cpp:36:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < primes.size () ; ++ i ) ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:52:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "asi.in" , "r" , stdin ) ; ^ main.cpp:53:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ( "asi.out" , "w" , stdout ) ; ^ main.cpp:60:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%lld" , & q ) ; ^ main.cpp:64:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ( "%lld%lld" , & a , & b ) ; ^