Instantiate A Singleton Object

[otisphat80]

Hello I am trying to create a singleton object for class I cant seem to create a instances correctly. I have seen very few examples of this in c++. My book is in Java and the few c++ examples I found don't seem to work. There is a lot of code in my program so I will just post the two relevant classes please let me know if you need more. Thanks.

Here is the pastebin page sorry I could not figure out how to create a link.

http://pastebin.com/2mbw1i4V 

[Cubbi]

There is rarely a need to use new in C++, and singletons are no exception: just return a reference:

    class GameBoard
    {
    public:
        static GameBoard& instance() {
            static GameBoard gb;
            return gb;
        }

then later in code, you can use
GameBoard::instance().get_contents_of_chosen_cell(Location(x,y))
or, if you want to save typing, name that reference:

GameBoard& r = GameBoard::instance();
...
r.get_contents_of_chosen_cell(Location(x,y))

Incidentally, why does it need to be a singleton? I don't see why there can't be more than one game board in existence.

[otisphat80]

Thanks for the help.Thhis is homework for a design patterns class.

[andywestken]

sorry I could not figure out how to create a link.

Links only work inside [code][/code] tags when commented

// http://pastebin.com/2mbw1i4V

or you can use [output][/output] tags

http://pastebin.com/2mbw1i4V

or [quote][/quote] tags

http://pastebin.com/2mbw1i4V

or no tags

http://pastebin.com/2mbw1i4V

Andy

[otisphat80]

Thanks man.

[otisphat80]

Another question this object is a two dim array and I need to populate it in the ctor how do I do that with a call to a static function.

GameBoard::GameBoard( )   /// populates gameBoard with empty organisms
{
	for(int i =0; i < ROWS; i++)
	     for(int j =0; j < COLUMNS; j++)
			m_gameboard[i][j] = Organism(Location(i, j),'*'); //<-- ??
}

[Cubbi]

That constructor is fine as-is. it will be called by instance() the first time it is called by user code

[otisphat80]

Yea thanks I think miss understood what was going on here. Thanks everyone.