Compilare: user.cpp: In function ‘int main()’: user.cpp:29:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xor.in","r",stdin); ^ user.cpp:30:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xor.out","w",stdout); ^ user.cpp:32:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&t,&mod); ^ user.cpp:34:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld%lld%lld",&x1,&y1,&x2,&y2); ^