[C++知识库]C++设计模式——16享元模式

#include<iostream>
#include<string>
#include<map>
#include<stdlib.h>
using namespace std;

string colors[] = 
      { "Red", "Green", "Blue", "White", "Black" };

class Shape
{
public:
    virtual void draw() = 0;
};

class Circle : public Shape
{
private:
    string color;
    int x;
    int y;
    int radius;

public:
    Circle(string color)
    {
        this->color = color;
    }

    void setX(int x)
    {
        this->x = x;
    }

    void setY(int y)
    {
        this->y = y;
    }

    void setRadius(int radius)
    {
        this->radius = radius;
    }

    void draw()
    {
        cout<<"Circle: Draw() [Color : "<<color<<", x : "<<x<<", y :"<<y<<", radius :"<<radius<<endl;
    }
};

class ShapeFactory
{
private:
    static map<string, Shape *> circleMap;
public:
    static Shape * getCircle(string color)
    {
        Circle * circle = (Circle*)circleMap[color];

        if (circle == NULL)
        {
            circle = new Circle(color);
            circleMap[color] = circle;
            cout<<"Creating circle of color : "<<color<<endl;
        }
        return circle;
    }
};

map<string, Shape *> ShapeFactory::circleMap;

string getRandomColor()
{
    return colors[rand()%(sizeof(colors)/sizeof(colors[0]))];
}

int getRandomX()
{
    return rand()%100;
}

int getRandomY()
{
    return rand()%100;
}

int main()
{
    for(int i=0; i < 20; ++i) {
         Circle *circle = 
            (Circle*)ShapeFactory::getCircle(getRandomColor());
         circle->setX(getRandomX());
         circle->setY(getRandomY());
         circle->setRadius(100);
         circle->draw();
    }
    return 0;
}