Selects a base format flag
  internal sets the justification format flag (adjustfield) to insert fill characters at an internal point enlarging the output representation up to the field width.
  left sets the justification format flag (adjustfield) to insert fill characters at the end enlarging the output representation up to the field width.
  right sets the justification format flag (adjustfield) to insert fill characters at the beginning enlarging the output representation up to the field width.

Parameters.

str

Stream object where to apply. This is a manipulator parameter.

Return Value.
  A reference to the stream object.

Example.

// modify adjustfield using manipulators
#include <iostream>
using namespace std;

int main () {
  int n;
  n=70;
  cout.width (10); cout << internal << n << endl;
  cout.width (10); cout << left << n << endl;
  cout.width (10); cout << right << n << endl;
  return 0;
}

          70
  70
          70

See also.
  flags, setf, unsetf
  ios_base class