<iomanip>

namespace std {
//      MANIPULATORS
T1 resetiosflags(ios_base::fmtflags mask);
T2 setiosflags(ios_base::fmtflags mask);
T3 setbase(int base);
template<class E>
    T4 setfill(E c);
T5 setprecision(int n);
T6 setw(int n);
    };

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);