Compilare: user.cpp: In function ‘int main()’: user.cpp:29:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("manhattan.in","r",stdin); ^ user.cpp:30:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("manhattan.out","w",stdout); ^ user.cpp:32:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&a1,&b1,&a2,&b2); ^