Manipulators in C++

Last Updated : 17 Jan, 2026

A manipulator is a special function in C++ that is used with input/output streams (like cin, cout ) to change the way data is shown or read. We can use manipulators when we want to :

Format numbers
Set precision (decimals)
Align text
Change number base (like decimal to hexadecimal)
Control spacing

They are most commonly used with cout for output formatting.

Types of Manipulators

There are various types of manipulators classified based on the type of entity they manipulate:

1. Output Stream Manipulators

These manipulators format how data is shown on the screen. The following table lists some common output stream manipulators:

Manipulator	What it Does	Example Usage
endl	Inserts a newline and flushes output	cout<<"Hello"<<endl;
flush	Flushes the output buffer immediately	cout<<flush;
setw(n)	Sets width of the next output field (spaces used for padding)	cout<<setw(10)<<42;
setprecision(n)	Sets the number of digits after decimal point	cout<< setprecision(3)<<3.14159;
fixed	Uses fixed-point notation for floating numbers.	cout<<fixed<<setprecision(2)<<3.14;
scientific	Uses scientific notation (exponential)	cout<< scientific << 1234.5;
showpoint	Always shows the decimal point (even if no digits after decimal)	cout<< showpoint<< 2.0;
noshowpoint	Hides unnecessary decimal point	cout<< noshowpoint<< 2.0;

Example:

Output

Hello
 42
3.14
3.142
3.142e+00
4.200e+01

2. Input Stream Manipulators

These manipulators help control how data is read from input streams. Following table lists some common input stream manipulators:

Manipulator	What it Does	Example Usage
ws	Skips all leading whitespace characters (spaces, tabs, newlines) before reading input	cin>>ws>>someString;
noskipws	Stops skipping whitespace (reads every character including spaces)	cin>> noskipws >> ch;

Example:

Input

s x

Output

c1: s, c2:

3. Boolean Manipulators

These manipulators control how boolean values (true/false) are displayed. Following table lists some common boolean manipulators:

Manipulator	What it Does	Example Usage
boolalpha	Prints true or false instead of 1 or 0.	cout<< boolalpha<< true;
noboolalpha	Prints 1 or 0 instead of true/ false	cout<< noboolalpha<< true;

Example:

Output

true
1

4. Alignment and Sign Manipulators

These control the alignment of output and how signs are shown. Following table lists some common alignment and sign manipulators:

Manipulator	What it Does	Example Usage
left	Left-aligns output in the given width	cout<< left<< setw(10) << 42;
right	Right-aligns output (default for numbers)	cout<< right<< setw(10)<< 42;
internal	Places the sign to the left, padding after the sign	cout<< internal << setw(10) << -42;
showpos	Shows a + sign for positive numbers	cout << showpos << 42;
noshowpos	Hides the + sign for positive numbers	cout<< noshowpos <<42;

Example:

Output

5. Base Manipulators

These manipulators change the number base used for integer output. Following table lists some common base manipulators:

Manipulator	What it Does	Example Usage
dec	Prints numbers in decimal (base 10)	cout << dec << 255;
hex	Prints numbers in hexadecimal (base 16)	cout << hex << 255;
oct	Prints numbers in octal (base 8)	cout << oct <<255;