Compilare: user.cpp: In function ‘int main()’: user.cpp:86:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hallway.in", "r", stdin); ^ user.cpp:87:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hallway.out", "w", stdout); ^ user.cpp:89:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf%d", &m, &n, &k); ^ user.cpp:92:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] double x, y; scanf("%lf%lf", &x, &y); ^