about sington patten

[w_j76]

please watch the sample about sington patten

class MazeFactory {
public:
static MazeFactory* Instance();
protected:
MazeFactory();
~ MazeFactory();
private:
static MazeFactory* _instance;
};

The corresponding implementation is

MazeFactory* MazeFactory::_instance = 0;

MazeFactory* MazeFactory::Instance () {
if (_instance == 0) {
_instance = new MazeFactory;
}
return _instance;
}

client call this class like this

MazeFactory * mazeclient=MazeFactory::Instance();

please notice there is a new but not delete ,
why it not cause memory leak?

[ShowMan]

a c++ function .