graph BT ios_base(ios_base)-->_Iosb(_Iosb) basic_ios(basic_ios)-->ios_base(ios_base) basic_istream(basic_istream)-->basic_ios(basic_ios) basic_ostream(basic_ostream)-->basic_ios(basic_ios) basic_ifstream(basic_ifstream)-->basic_istream(basic_istream) basic_istringstream(basic_istringstream)-->basic_istream(basic_istream) basic_iostream(basic_iostream)-->basic_istream(basic_istream) basic_ofstream(basic_ofstream)-->basic_ostream(basic_ostream) basic_ostringstream(basic_ostringstream)-->basic_ostream(basic_ostream) basic_iostream(basic_iostream)-->basic_ostream(basic_ostream) basic_fstream(basic_fstream)-->basic_iostream(basic_iostream) basic_stringstream(basic_stringstream)-->basic_iostream(basic_iostream)