29 Input/output library [input.output]

29.5 Iostreams base classes [iostreams.base]

29.5.6 ios_­base manipulators [std.ios.manip] basefield manipulators [basefield.manip]

Each function specified in this subclause is a designated addressable function ([namespace.std]).
ios_base& dec(ios_base& str);
Effects: Calls str.setf(ios_­base​::​dec, ios_­base​::​basefield).
Returns: str297.
ios_base& hex(ios_base& str);
Effects: Calls str.setf(ios_­base​::​hex, ios_­base​::​basefield).
Returns: str.
ios_base& oct(ios_base& str);
Effects: Calls str.setf(ios_­base​::​oct, ios_­base​::​basefield).
Returns: str.
The function signature dec(ios_­base&) can be called by the function signature basic_­ostream& stream​::​operator<<(ios_­base& (*)(ios_­base&)) to permit expressions of the form cout << dec to change the format flags stored in cout.