Page 271 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes Manipulators are special functions that can be included in these statements to alter the format
parameters of a stream. The table given below shows some important manipulator functions
that are frequently used. To access these manipulators, the file iomanip.h should be included in
the program.

Manipulators Equivalent ios function
setw() width()
setprecision() precision()
Setfill() fill()
setiosflags() setf()
resetiosflags() unsetf()

In addition to these functions supported by the C++ library, we can create our own manipulator
functions to provide any special output formats.

Task Analyze the difference between the advantages of unformatted and formatted I/O.

Self Assessment

Fill in the blanks:

8. ……………………….. input/output transfers the internal binary representation of the data
directly between memory and the file.
9. Unformatted data files can only be moved easily to and from computers that share the
same internal………………………...
10. Formatted input/output is more computationally ………………………. than unformatted
input/output.
11. The …………………… class contains a large number of member functions that could be
used to format the output in a number of ways.
12. …………………………. are special functions that can be included in these statements to
alter the format parameters of a stream.

12.4 Managing Output with Manipulators

These operators are used to format the data display. The commonly used manipulators are endl
and setw.
1. endl manipulator when used causes a linefeed to be inserted. For example,

cout <<“m=” <<m <<endl
<<“n=” <<n <<endl
<<“p=” <<p <<endl;
would cause the output as:
Assuming the values of variables as 2597, 14 and 175.
m = 2597

264 LOVELY PROFESSIONAL UNIVERSITY