[GeekBand][C++设计模式]第二周作业

P.S. 这周居然日平均上班时间达到了19h。。。已跪，救命

用的工厂方法

class DrawSys
{
private:
    Shape shape;
public:
    void draw() {/*...*/ }
};

class Shape
{
private:
    ShapeFactory* shape;
public:
    Shape(ShapeFactory* shapefac)
        :shape(shapefac)
    {}
    ~Shape()
    {
        delete shape;
    }
    void Draw()
    {
        IShape* ishape = shape->CreateShape();
        ishape->Drawing();
        delete ishape;
    }
};

class IShape
{
public:
    virtual void Drawing() = 0;
    virtual ~IShape() {}
};

class Line :public IShape
{
public:
    virtual void Drawing() {/*...*/ }
};

class Rec :public IShape
{
public:
    virtual void Drawing() {/*...*/ }
};

class Circle :public IShape
{
public:
    virtual void Drawing() {/*...*/}
};

class ShapeFactory
{
public:
    virtual IShape* CreateShape() = 0;
    virtual ~ShapeFactory() {}
};

class LineFactory : public ShapeFactory
{
public:
    IShape* CreateShape()
    {
        return new Line();
    }
};

class RecFactory : public ShapeFactory
{
public:
    IShape* CreateShape()
    {
        return new Rec();
    }
};

class CircleFactory : public ShapeFactory
{
public:
    IShape* CreateShape()
    {
        return new Circle();
    }
};