Compilare: user.cpp: In function ‘int main()’: user.cpp:78:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("alee.in", "r", stdin); ^ user.cpp:79:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("alee.out", "w", stdout); ^ user.cpp:81:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &m); ^ user.cpp:83:45: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &x, &y), A[x][y] = -1; ^ user.cpp:84:59: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d", &start.f, &start.s, &End.f, &End.s); ^