Compilare: user.cpp: In function ‘int main()’: user.cpp:50:13: warning: unused variable ‘sgn’ [-Wunused-variable] int sgn = (nr&1 ? 1 : -1); ^ user.cpp:11:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cowfood.in","r",stdin); ^ user.cpp:12:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cowfood.out","w",stdout); ^