Insert null character.
  Inserts the null character ('\0') in the stream.

Parameters.

os

Stream in which the insertion has to be performed.
This is a manipulator parameter that is automatically assumed if used with insertion operator (operator<<).

Return Value.
  A reference to the stream object (parameter os).

Basic template declaration:

template <class charT, class traits>   basic_ostream<charT,traits>& ends ( basic_ostream<charT,traits>& os );

See also.
  ostream class