Formatting

endl	now	Write a newline ('\n') and flush buffer.
setw(n)	next	Sets minimum field width on output. This sets the minimum size of the field - a larger number will use more columns. Applies only to the next element inserted in the output. Use left and right to justify the data appropriately in the field. Output is right justified by default. Equivalent to cout.width(n); To print a column of right justified numbers in a seven column field: cout << setw(7) << n << endl;
width(n)	next	Same as setw(n).
left	next	Left justifies output in field width. Only useful after setw(n).
right	next	Right justifies output in field width. Since this is the default, it is only used to override the effects of left. Only useful after setw(n).
setfill(ch)	all	Only useful after setw. If a value does not entirely fill a field, the character ch will be used to fill in the other characters. Default value is blank. Same effects as cout.fill(ch) For example, to print a number in a 4 character field with leading zeros (eg, 0007): cout << setw(4) << setfill('0') << n << endl;

Floating Point Output

Manipulator	Range	Description

setprecision(n)	all	Sets the number of digits printed to the right of the decimal point. This applies to all subsequent floating point numbers written to that output stream. However, this won't make floating-point "integers" print with a decimal point. It's necessary to use fixed for that effect. Equivalent to cout.precision(n);
fixed	all	Use fixed point notation for floating-point numbers. Opposite of scientific. If no precision has already been specified, it will set the precision to 6.
scientific	all	Formats floating-point numbers in scientific notation. Opposite of fixed.

Bool Output

Manipulator	Range	Description

boolalpha
noboolalpha

all

Uses alphabetic representation (true and false) for bool values. Turned off with noboolalpha.

Input

Manipulator	Range	Description

skipws noskipws	all	For most input values (eg, integers and floating-point numbers), skipping initial whitespace (eg, blanks) is very useful. However, when reading characters, it is often desired to read the whitespace characters as well as the non-spacing characters. The these I/O manipulators can be used to turn whitespace skipping off and on. Eg, cin >> noskipws; turns whitespace skipping off for all subseqent cin input.
ws	now	Reads and ignores whitespace at the current position.

Example Code

Example 1

Example 2

#include "stdafx.h"

#include <iostream>

#include <iomanip>

using namespace std;

int main()

{

const float tenth = 0.1;

const float one = 1.0;

const float big = 1234567890.0;

cout << "A. " << tenth << ", " << one << ", " << big << endl;

cout << "B. " << fixed << tenth << ", " << one << ", " << big << endl;

cout << "C. " << scientific << tenth << ", " << one << ", " << big << endl;

cout << "D. " << fixed << setprecision(3) << tenth << ", " << one << ", " << big << endl;

cout << "E. " << setprecision(20) << tenth << endl;

cout << "F. " << setw(8) << setfill('*') << 34 << 45 << endl;

cout << "G. " << setw(8) << 34 << setw(8) << 45 << endl;

return 0;

}

Output for Example Code

Using Casting

#include "stdafx.h"

#include <iostream> //for input and output

#include <iomanip> //for format manipulation

using namespace std;

int main ()

{

double aDouble = 5.123456;

int anInteger = 5;

cout<<"THE ORIGINAL VALUES"<<endl;

cout<<"aDouble is: "<<aDouble<<endl;

cout<<"anInteger is "<<anInteger<<endl;

cout<<endl;

cout<<"ILLUSTRATING CASTING"<<endl;

cout <<"aDouble converted to an integer is: "<<(int)aDouble<<endl;

cout <<"anInteger converted to a double is: "<<(double)anInteger<<endl;

cout <<endl;

cout<<"CASING DOES NOT CHANGE ORIGINAL VALUES"<<endl;

cout <<"aDouble is still "<<aDouble<<endl;

cout <<"anInteger is still "<<anInteger<<endl;

cout <<endl;

cout<<"ILLUSTRATING setprecison()"<<endl;

cout<<fixed;

cout<<setprecision(4);

cout<<"aDouble with 4 decimal places is "<<aDouble<<endl;

cout<<setprecision(2);

cout<<"aDouble with 2 decimal places is "<<aDouble<<endl;

return 0;

}