Compilare: user.cpp: In function ‘int32_t main()’: user.cpp:64:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<ar.size();i++) ^ user.cpp:18:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("catun.in","r",stdin); ^ user.cpp:19:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("catun.out","w",stdout); ^