std:: setfill

From cppreference.com
< cpp ‎ | io ‎ | manip
Defined in header <iomanip>
template < class CharT >
/*unspecified*/ setfill ( CharT c ) ;

When used in an expression out << setfill ( c ) sets the fill character of the stream out to c .

Parameters

c - new value for the fill character

Return value

An object of unspecified type such that

where the function f is defined as:

template<class CharT, class Traits>
void f(std::basic_ios<CharT, Traits>& str, CharT c)
{
    // set fill character
    str.fill(c);
}

Notes

The current fill character may be obtained with std::ostream::fill .

Example

#include <iomanip>
#include <iostream>
 
int main()
{
    std::cout << "default fill: [" << std::setw(10) << 42 << "]\n"
              << "setfill('*'): [" << std::setfill('*')
                                   << std::setw(10) << 42 << "]\n";
}

Output:

default fill: [        42]
setfill('*'): [********42]

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 183 C++98 setbase could only be used with
streams of type std::ostream
usable with any output
character stream

See also

manages the fill character
(public member function of std::basic_ios<CharT,Traits> )
sets the placement of fill characters
(function)
changes the width of the next input/output field
(function)