Bridge.cpp

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// From:
// http://en.wikipedia.org/wiki/Bridge_pattern

#include <iostream>

using namespace std;

/* Implementor*/
class DrawingAPI {
public:
    virtual void drawCircle(double x, double y, double radius) = 0;
    virtual ~DrawingAPI() {}
};

/* Concrete ImplementorA*/
class DrawingAPI1 : public DrawingAPI {
public:
    void drawCircle(double x, double y, double radius) {
        cout << "API1.circle at " << x << ':' << y << ' ' << radius << endl;
    }
};

/* Concrete ImplementorB*/
class DrawingAPI2 : public DrawingAPI {
public:
    void drawCircle(double x, double y, double radius) {
        cout << "API2.circle at " << x << ':' << y << ' ' <<  radius << endl;
    }
};

/* Abstraction*/
class Shape {
public:
    virtual ~Shape() {}
    virtual void draw() = 0;
    virtual void resizeByPercentage(double pct) = 0;
};

/* Refined Abstraction*/
class CircleShape : public Shape {
public:
    CircleShape(double x, double y,double radius, DrawingAPI *drawingAPI) :
      m_x(x), m_y(y), m_radius(radius), m_drawingAPI(drawingAPI)
      {}
      void draw() {
          m_drawingAPI->drawCircle(m_x, m_y, m_radius);
      }
      void resizeByPercentage(double pct) {
          m_radius *= pct;
      }
private:
    double m_x, m_y, m_radius;
    DrawingAPI *m_drawingAPI;
};

int main(void) {
    CircleShape circle1(1,2,3,new DrawingAPI1());
    CircleShape circle2(5,7,11,new DrawingAPI2());
    circle1.resizeByPercentage(2.5);
    circle2.resizeByPercentage(2.5);
    circle1.draw();
    circle2.draw();
    return 0;
}

/*Output
API1.circle at 1:2 7.5
API2.circle at 5:7 27.5
*/

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