Changing stream properties using manipulators

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Changing stream properties using manipulators

For convenience, manipulators provide a way to change certain properties of streams, or otherwise affect them, in the middle of expressions involving << or >>.

For example, you might use the following input statement to produce |**234| as output.

cout << "|" << setfill('*') << setw(5) << 234 << "|";

Manipulators that take an argument require #include <iomanip.h>.

ws
Manipulator

Skips whitespace.

flush
Manipulator

Flushes an output stream. For instance, the input,

cout<<...<<flush;

, has the same effect as the following input.

cout<<...; cout.flush();.

endl
Manipulator

Writes an end of line character,

, then flushes the output stream.

ends
Manipulator

Writes the string terminator character,

setprecision (int signif)
Manipulator

You can change the value of

ios::precision

expressions with the manipulator,

setprecision(signif)

; for instance, use the following input to print

4.6

. Manipulators such as

setprecision(signif)

that take an argument require

#include <iomanip.h>

cout << setprecision(2) << 4.567;

setw (int n)
Manipulator

You can change the value of

ios::width

expressions with the manipulator

setw( n)

; use the following input as an example.

cout << setw(5) << 234;

This input prints

234

with two leading spaces.

Requires

#include <iomanip.h>

setbase (int base)
Manipulator

Where

base

is one of

(decimal),

(octal), or

(hexadecimal), change the base value for numeric representations.

Requires

#include <iomanip.h>

dec
Manipulator

Select decimal base; equivalent to

setbase(10)

hex
Manipulator

Select hexadecimal base; equivalent to

setbase(16)

oct
Manipulator

Select octal base; equivalent to

setbase(8)

setfill (char padding)
Manipulator

Set the

padding

character, in the same way as

ios::fill

Requires

#include <iomanip.h>

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