std::setw

Header: <iomanip>

When used in an expression out « std::setw(n) or in » std::setw(n), sets the width parameter of the stream out or in to exactly n.

# Declarations

/* unspecified */ setw( int n );

# Parameters

• n: new value for width

# Return value

An object of unspecified type such that

# Notes

The width property of the stream will be reset to zero (meaning “unspecified”) if any of the following functions are called:

The exact effects this modifier has on the input and output vary between the individual I/O functions and are described at each operator« and operator» overload page individually.

# Example

#include <iomanip>
#include <iostream>
#include <sstream>
 
int main()
{
    std::cout << "no setw: [" << 42 << "]\n"
              << "setw(6): [" << std::setw(6) << 42 << "]\n"
              << "no setw, several elements: [" << 89 << 12 << 34 << "]\n"
              << "setw(6), several elements: [" << 89 << std::setw(6) << 12 << 34 << "]\n";
 
    std::istringstream is("hello, world");
    char arr[10];
 
    is >> std::setw(6) >> arr;
    std::cout << "Input from \"" << is.str() << "\" with setw(6) gave \""
              << arr << "\"\n";
}

# Defect reports

# See also

• width
• setfill
• internalleftright
• showbasenoshowbase