Compilare: user.cpp: In function ‘void Read_All()’: user.cpp:19:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d", &N, &M, &C); ^ user.cpp:25:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &mat[i & 1][j]); ^ user.cpp:30:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &cost[i]); ^ user.cpp: In function ‘int main()’: user.cpp:35:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("tv.in", "r", stdin); ^ user.cpp:36:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("tv.out", "w", stdout); ^