Compilare: user.cpp: In function ‘int main()’: user.cpp:68:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.in","r",stdin); ^ user.cpp:69:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.out","w",stdout); ^ user.cpp:71:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld",&A,&B,&C); ^