Include the iostreams standard header <iomanip> to define several manipulators that each take a single argument. Each of these manipulators returns an unspecified type, called T1 through T6 here, that overloads both basic_istream<E, T>::operator>> and basic_ostream<E, T>::operator<<. Thus, you can write extractors and inserters such as:
cin >> setbase(8);
cout << setbase(8);