std::left, std::right, std::internal

Defined in header `<ios>`
std::ios_base& left( std::ios_base& str );	(1)
std::ios_base& right( std::ios_base& str );	(2)
std::ios_base& internal( std::ios_base& str );	(3)

Modifies the default positioning of the fill characters. left and right apply to any output, internal applies to integer, floating-point, and monetary output. Has no effect on input.

1) sets the adjustfield of the stream str to left as if by calling str.setf(std::ios_base::left, std::ios_base::adjustfield).

2) sets the adjustfield of the stream str to right as if by calling str.setf(std::ios_base::right, std::ios_base::adjustfield).

3) sets the adjustfield of the stream str to internal as if by calling str.setf(std::ios_base::internal, std::ios_base::adjustfield).

This is an I/O manipulator. It may be called with an expression such as out << std::left for any out of type std::basic_ostream or with an expression such as in >> std::left for any in of type std::basic_istream.

Parameters

str

reference to I/O stream

Return value

str (reference to the stream after manipulation).

Example

#include <iostream>
#include <iomanip>
#include <locale>
 
int main()
{
    std::cout.imbue(std::locale("en_US.utf8"));
    std::cout << "Left fill:\n" << std::left << std::setfill('*')
              << std::setw(12) << -1.23  << '\n'
              << std::setw(12) << std::hex << std::showbase << 42 << '\n'
              << std::setw(12) << std::put_money(123, true) << "\n\n";
 
    std::cout << "Internal fill:\n" << std::internal
              << std::setw(12) << -1.23  << '\n'
              << std::setw(12) << 42 << '\n'
              << std::setw(12) << std::put_money(123, true) << "\n\n";
 
    std::cout << "Right fill:\n" << std::right
              << std::setw(12) << -1.23  << '\n'
              << std::setw(12) << 42 << '\n'
              << std::setw(12) << std::put_money(123, true) << '\n';
}

Output:

Left fill:
-1.23*******
0x2a********
USD *1.23***
 
Internal fill:
-*******1.23
0x********2a
USD ****1.23
 
Right fill:
*******-1.23
********0x2a
***USD *1.23

setw	changes the width of the next input/output field (function)
setfill	changes the fill character (function template)

std::left, std::right, std::internal

Parameters

Return value

Example

See also