An output manipulator function has the syntax:
ostream &manipulator_name(ostream &stream)
An input manipulator function has the syntax:
istream &manipulator_name(istream &stream)
Some points about manipulators:
1) A manipulator is used to combine several individual input/output operations. Thus, it simplifies the code.
2) It is also used for doing input/output operations on non-standard devices.
3) It makes a C++ program simple and effective.