Grusel++ of the month

/******************************************************************************/
/*                                                                            */
/*                                                             FILE: JUNE.CPP */
/*                                                                            */
/*  Hello world implemented with an io manipulator                            */
/*  ==============================================                            */
/*                                                                            */
/*  Compiled and tested with Visual C++ V6.0                                  */
/*                                                                            */
/*  V1.00   30-JUN-2000   P. Tellenbach   http://www.heimetli.ch/             */
/*                                                                            */
/******************************************************************************/

#include <iostream>

using namespace std ;

ostream& HelloWorld( ostream& os )
{
  return( os << "Hello world !" ) ;
}

int main()
{
   return (cout << HelloWorld << endl).good() ;
}

Update 16. June 2020

This program still compiles and runs without any changes.

Update 30. June 2025

The program needed no change, but I corrected the return value.

/******************************************************************************/
/*                                                                            */
/*                                                             FILE: JUNE.CPP */
/*                                                                            */
/*  Hello world implemented with an io manipulator                            */
/*  ==============================================                            */
/*                                                                            */
/*  Compiled and tested with Visual C++ V6.0                                  */
/*                                                                            */
/*  V1.00   30-JUN-2000   P. Tellenbach   http://www.heimetli.ch/             */
/*                                                                            */
/*  Compiled and tested with g++ V11.2.0                                      */
/*                                                                            */
/*  V1.10   30-JUN-2025   P. Tellenbach   https://www.heimetli.ch             */
/*                                                                            */
/******************************************************************************/

#include <iostream>

using namespace std ;

ostream& HelloWorld( ostream& os )
{
  return( os << "Hello world !" ) ;
}

int main()
{
   return !(cout << HelloWorld << endl).good() ;
}