std::setw
std::setw
| Defined in header | | |
|---|---|---|
| /*unspecified*/ setw( int n | | |
When used in an expression out << setw(n) or in >> setw(n), sets the width parameter of the stream out or in to exactly n.
Parameters
| n | - | new value for width |
|---|
Return value
Returns an object of unspecified type such that if str is the name of an output stream of type std::basic_ostream<CharT, Traits> or std::basic_istream<CharT, Traits>, then the expression str << setw(n) or str >> setw(n) behaves as if the following code was executed:
str.width(n
Notes
The width property of the stream will be reset to zero (meaning "unspecified") if any of the following functions are called:
- Input
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 <sstream>
#include <iostream>
#include <iomanip>
int main()
{
std::cout << "no setw:" << 42 << '\n'
<< "setw(6):" << std::setw(6) << 42 << '\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";
}
Output:
no setw:42
setw(6): 42
setw(6), several elements: 89 1234
Input from "hello, world" with setw(6) gave "hello"
See also
| width | manages field width (public member function of std::ios_base) |
|---|---|
| setfill | changes the fill character (function template) |
| internalleftright | sets the placement of fill characters (function) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
