Manipulators in C++

Manipulators are helper functions that make it possible to control input/output streams using operator<<() or operator>>()

The advantage of using manipulators, inserters, and extractors over regular member functions for a class is that the stream-and-file metaphor is maintained. In the long run, this makes for code that is easier to read, maintain, and use. The supplier (writer) of a class has to do a little more work up front, but ultimately the supplier's job is made easier and the user of a class benefits immediately.