sorry folks...i had quoted the question in the book (by Stroustrup) wrongly..
the actual question was
write manipulators that turn character echoing on and off
this is the correct one. unlike a command, itz just a quote..hope you understand.
pease refer this for more details.
its on the exercise section of the chapter 21.Streams which is at the end of it, and page is 656.
The C++ Programming Language 3rd ed
from the Creator Of C++,
Addison Wesley Publications.