C++ - How to reset the output stream manipulator flags

Question

I've got a line of code that sets the fill value to a '-' character in my output, but need to reset the setfill flag to its default whitespace character. How do I do that?

cout << setw(14) << "  CHARGE/ROOM" << endl;
cout << setfill('-') << setw(11) << '-' << "  " << setw(15) << '-' << "   " << setw(11) << '-' << endl;

I thought this might work:

cout.unsetf(ios::manipulatorname) // Howerver I dont see a manipulator called setfill

Am I on the wrong track?

Answer 1

You can use the ios::fill() function to set and restore the fill character instead.

http://www.cplusplus.com/reference/iostream/ios/fill/

#include <iostream>
using namespace std;

int main () {
  char prev;

  cout.width (10);
  cout << 40 << endl;

  prev = cout.fill ('x');
  cout.width (10);
  cout << 40 << endl;

  cout.fill(prev);

  return 0;
}

Answer 2

Have a look at the Boost.IO_State_Savers, providing RAII-style scope guards for the flags of an iostream.

Example:

{
  boost::io::ios_all_saver guard(cout); // Saves current flags and format

  cout << setw(14) << "  CHARGE/ROOM" << endl;
  cout << setfill('-') << setw(11) << '-' << "  " << setw(15) << '-' << "   " << setw(11) << '-' << endl;
// dtor of guard here restores flags and formats
}

More specialized guards (for only fill, or width, or precision, etc... are also in the library. See the docs for details.