Compilare: main.cpp: In function 'int main()': main.cpp:29:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("abx.in" , "r" , stdin); ^ main.cpp:30:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("abx.out" , "w" , stdout); ^ main.cpp:36:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%lld" , &a); ^