Compilare: user.cpp: In function ‘int main()’: user.cpp:81:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b.size();++i) ^ user.cpp:28:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in","r",stdin); ^ user.cpp:29:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out","w",stdout); ^