Compilare: user.cpp: In function ‘int main()’: user.cpp:44:9: warning: variable ‘id’ set but not used [-Wunused-but-set-variable] int id = 0; ^ user.cpp:38:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scara2.in", "r", stdin); ^ user.cpp:39:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("scara2.out", "w", stdout); ^ user.cpp:42:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &H, &N, &M, &P); ^