我的 Design Pattern 之旅 [1]：Strategy Pattern (6) - C++ Template 實現

Strategy Pattern ISO C++ Template 實現：編譯期多態與零開銷抽象

核心代碼

template 
class Grapher {
private: T _drawTemplate;
public: void drawShape() const { _drawTemplate.draw(); }
};

class Triangle { public: void draw() const { cout << "Draw Triangle" << endl; } };
class Circle { public: void draw() const { cout << "Draw Circle" << endl; } };
class Square { public: void draw() const { cout << "Draw Square" << endl; } };

int main() {
    Grapher grapher; grapher.drawShape();
    Grapher grapher2; grapher2.drawShape();
}

執行結果

Draw Square
Draw Circle

三種實現對比

C# 2.0 引入泛型後，同樣可用 Generics 實現 Strategy Pattern (見前文)。