Compilare: user.cpp: In function ‘int main()’: user.cpp:10:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cal.in","r",stdin); freopen("cal.out","w",stdout); ^ user.cpp:10:60: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cal.in","r",stdin); freopen("cal.out","w",stdout); ^ user.cpp:11:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &c.x, &c.y, &s, &n); ^ user.cpp:13:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &p.x, &p.y); ^