Compilare: user.cpp: In function ‘int main()’: user.cpp:112:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size(); ++ i) ^ user.cpp:113:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] cout << ans[i] << " \n"[i + 1 == ans.size()]; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:14:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:36:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^