factory method

class shape
{
public:
 shape() {};
 ~shape() {};

 virtual void draw() = 0;
};

 

class square : public shape
{
public:
 square() {};
 ~square() {};

 void draw()
 {
  cout << "square is drawn\n" << endl;
 }
};

 

class circle : public shape
{
public:
 circle() {};
 ~circle() {};

 void draw()
 {
  cout << "circle is drawn\n"  << endl;
 }
};

 

int main()
{
 shape* pShape = (circle*)new circle();

 pShape->draw();

 return 1;
}

 

http://www.javacamp.org/designPattern/factory.html

http://en.wikipedia.org/wiki/Factory_method_pattern