crash-course-4.4.cc

/*
 * Copyright (C) 2012 Nicolas P. Rougier
 *
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either  version 3 of the  License, or (at your  option) any later
 * version.
 *
 * This program is  distributed in the hope that it will  be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR  A  PARTICULAR PURPOSE.  See  the GNU  General  Public  License for  more
 * details.
 *
 * You should have received a copy  of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
#include <iostream>

class Singleton
{

public:
   static Singleton * instance( void )
   {
	   if( !_instance )
       {
           _instance = new Singleton;
       }
       return _instance;
   }

private:
   Singleton( void )
   { };

   Singleton( Singleton const & other )
   { };

   Singleton & operator=( Singleton const & other )
   {
       return *this;
   };

   static Singleton* _instance;
};

Singleton *Singleton::_instance = 0;

int main( int argc, char **argv )
{
    Singleton *singleton = Singleton::instance();

    delete singleton;
    return 0;
}