std::basic_ios<CharT,Traits>::fill
Min standard notice:
Manages the fill character used to pad the output conversions to the specified field width.
# Declarations
CharT fill() const;
CharT fill( CharT ch );
# Parameters
ch: the character to use as fill character
# Return value
The fill character before the call to the function.
# Example
#include <iomanip>
#include <iostream>
int main ()
{
std::cout << "With default setting : [" << std::setw(10) << 40 << "]\n";
char prev = std::cout.fill('x');
std::cout << "Replaced '" << prev << "' with '"
<< std::cout.fill() << "': [" << std::setw(10) << 40 << "]\n";
}