Static Factory Design Pattern

StaticFactoryDesignPattern.cpp

#include <iostream>
#include <string>

using namespace std;

// Abstract Base Class
class Shape {
  public:
	virtual void Draw() = 0;
	virtual ~Shape();
	// Static class to create objects
	// Change is required only in this function to create a new object type
	static Shape *Create(string type);
};

class Circle : public Shape {
  public:
	~Circle();
	void Draw() { cout << "I am circle" << endl; }
	friend class Shape;
};
Circle::~Circle() {}
class Square : public Shape {
  public:
	~Square();
	void Draw() { cout << "I am square" << endl; }
	friend class Shape;
};
Square::~Square() {}
Shape *Shape::Create(string type)
{
	if (type == "circle")
	return new Circle();
	if (type == "square")
	return new Square();
	return NULL;
}

int main()
{
	// Give me a circle
	Shape *obj1 = Shape::Create("circle");

	// Give me a square
	Shape *obj2 = Shape::Create("square");

	obj1->Draw();
	obj2->Draw();
	return 0;
}