C++ Manipulators

• Manipulators are operators used in C++ for formatting output. The data is manipulated by the programmer’s choice of display.
• In this C++ tutorial, you will learn what a manipulator is, endl manipulator, setw manipulator, setfill manipulator and setprecision manipulator are all explained along with syntax and examples.

endl Manipulator:

• This manipulator has the same functionality as the ‘n’ newline character.

For example:

 

setw Manipulator:

• This manipulator sets the minimum field width on output.

• Here setw causes the number or string that follows it to be printed within a field of x characters wide and x is the argument set in setw manipulator.
• The header file that must be included while using setw manipulator is .

Example:

#include <iostream>
#include <iomanip> 
 
void main( )
{
int x1=123,x2= 234, x3=789;
cout << setw(8) << "Exforsys" << setw(20) << "Values" << endl
<< setw(8) << "test123" << setw(20)<< x1 << endl
<< setw(8) << "exam234" << setw(20)<< x2 << endl
<< setw(8) << "result789" << setw(20)<< x3 << endl;
}

Output:

test                  123
exam                  234
result                  789

 

setfill Manipulator:

• This is used after setw manipulator.
• If a value does not entirely fill a field, then the character specified in the setfill argument of the manipulator is used for filling the fields.

Example:

#include <iostream>
#include <iomanip>
void main()
{
cout << setw(15) << setfill('*') << 99 << 97 << endl;
}

Output:

********9997

 

setprecision Manipulator:

• The setprecision Manipulator is used with floating point numbers.
• It is used to set the number of digits printed to the right of the decimal point.
• This may be used in two forms:

1. fixed
2. scientific

• These two forms are used when the keywords fixed or scientific are appropriately used before the setprecision manipulator.
• The keyword fixed before the setprecision manipulator prints the floating point number in fixed notation.
• The keyword scientific, before the setprecision manipulator, prints the floating point number in scientific notation.

 

Example:

#include <iostream>
#include <iomanip>
void main( )
{
float x = 0.1;
cout << fixed << setprecision(3) << x << endl;
cout << scientific << x << endl;
}

Output:

0.100
1.000e-001

 

• The first cout statement contains fixed notation and the setprecision contains argument 3.
• This means that three digits after the decimal point and in fixed notation will output the first cout statement as 0.100. The second cout produces the output in scientific notation.
• The default value is used since no setprecision value is provided.

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