设计模式——装饰器模式（C++实现）

 #include <iostream>
 #include <string>

 using namespace std;

 class Component
 {
 public:
         virtual void operation() = ;
 };

 class ConcreteComponentA: public Component
 {
 public:
         virtual void operation()
         {
                 cout<< "ConcreteComponentA....."<< endl;
         }
 };

 class ConcreteComponentB: public Component
 {
 public:
         virtual void operation()
         {
                 cout<< "ConcreteComponentB....."<< endl;
         }
 };

 class Decorator:public Component
 {
 public:
         Decorator(Component* pCom):component(pCom){}

         virtual void operation() = ;

         Component* component;
 };

 class ConcreteDecoratorA: public Decorator
 {
 public:
         ConcreteDecoratorA(Component* pCom):Decorator(pCom){}

         void operation()
         {
                 component->operation();
                 AddBehavior();
         }

         void AddBehavior()
         {
                 cout<< "ConcreteDecoratorA....."<< endl;
         }
 };

 class ConcreteDecoratorB: public Decorator
 {
 public:
         ConcreteDecoratorB(Component* pCom):Decorator(pCom){}

         void operation()
         {
                 component->operation();
                 AddBehavior();
         }

         void AddBehavior()
         {
                 cout<< "ConcreteDecoratorB....."<< endl;
         }
 };

 int main(int argc, char* argv[])
 {
         ConcreteComponentB* ccB = new ConcreteComponentB();

         ConcreteDecoratorA* cdA1 = new ConcreteDecoratorA(ccB);

         ConcreteDecoratorA* cdA2 = new ConcreteDecoratorA(cdA1);

         ConcreteDecoratorB* cdB1 = new ConcreteDecoratorB(cdA1);

         cdA1->operation();cout<< endl;
         cdA2->operation();cout<< endl;
         cdB1->operation();cout<< endl;

         return ;
 }

 ///////////////////////////
 [root]$ ./decorator
 ConcreteComponentB.....
 ConcreteDecoratorA.....

 ConcreteComponentB.....
 ConcreteDecoratorA.....
 ConcreteDecoratorA.....

 ConcreteComponentB.....
 ConcreteDecoratorA.....
 ConcreteDecoratorB.....