Compilare: user.cpp: In function ‘void eval()’: user.cpp:52:14: warning: unused variable ‘ok’ [-Wunused-variable] bool ok = 0; ^ user.cpp: In function ‘int main()’: user.cpp:25:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.in", "r", stdin); ^ user.cpp:26:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.out", "w", stdout); ^ user.cpp:27:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s); ^