Compilare: user.cpp: In function ‘int main()’: user.cpp:51:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < buffer.size (); i++) ^ user.cpp:18:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("zeul.in", "rt", stdin); ^ user.cpp:19:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("zeul.out", "wt", stdout); ^