C++

Reference

<ios>

basic_ios

public member function
<ios> <iostream>

std::basic_ios::fill

get (1)
char_type fill() const;
set (2)
char_type fill (char_type fillch);
Get/set fill character
The first form (1) returns the fill character.

The second form (2) sets fillch as the new fill character and returns the fill character used before the call.

The fill character is the character used by output insertion functions to fill spaces when padding results to the field width.

The parametric manipulator setfill can also be used to set the fill character.

Parameters

fillch
the new fill character.
Member type char_type is the type of characters used by the stream (i.e., its first class template parameter, charT).

Return Value

The value of the fill character before the call.
Member type char_type is the type of characters used by the stream (i.e., its first class template parameter, charT).

Example

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// using the fill character
#include <iostream>     // std::cout

int main () {
  char prev;

  std::cout.width (10);
  std::cout << 40 << '\n';

  prev = std::cout.fill ('x');
  std::cout.width (10);
  std::cout << 40 << '\n';

  std::cout.fill(prev);

  return 0;
}

Output:
        40
xxxxxxxx40


Data races

Accesses (1) or modifies (2) the stream object.
Concurrent access to the same stream object may cause data races.

Exception safety

Basic guarantee: if an exception is thrown, the stream is in a valid state.

See also

setfill
Set fill character (function)
ios_base::width
Get/set field width (public member function)