774-C++设计模式 - 装饰器模式

装饰器模式 Decorator（结构型模式—类和对象的组合，组合方式）
该设计模式的目的是：负责功能扩展

通过子类实现功能增强的问题：
为了增强现有类的功能，通过实现子类的方式，重写接口，是可以完成功能扩展的，但是代码中有太多的子类添加进来了！！！

所以我们通过装饰器模式看看效果如何！！！

#include 
#include 
using namespace std;



class Car//抽象基类
{
public:
	virtual void show() = 0;
};

//三个实体的汽车类
class Bmw : public Car
{
public:
	void show() 
	{
		cout << "这是一辆宝马汽车，配置有：基类配置";
	}
};
class Audi : public Car
{
public:
	void show()
	{
		cout << "这是一辆奥迪汽车，配置有：基类配置";
	}
};
class Benz : public Car
{
public:
	void show()
	{
		cout << "这是一辆奔驰汽车，配置有：基类配置";
	}
};

//装饰器1  定速巡航
class ConcreteDecorator01 : public Car
{
public:
	ConcreteDecorator01(Car *p) :pCar(p) {}
	void show()
	{
		pCar->show();
		cout << ",定速巡航";
	}
private:
	Car *pCar;
};
//装饰器2  自动刹车 
class ConcreteDecorator02 : public Car
{
public:
	ConcreteDecorator02(Car *p) :pCar(p) {}
	void show()
	{
		pCar->show();
		cout << ",自动刹车";
	}
private:
	Car *pCar;
};
//装饰器3  车道偏离 
class ConcreteDecorator03 : public Car
{
public:
	ConcreteDecorator03(Car *p) :pCar(p) {}
	void show()
	{
		pCar->show();
		cout << ",车道偏离";
	}
private:
	Car *pCar;
};

int main()
{
	Car *p1 = new ConcreteDecorator01(new Bmw());
	p1 = new ConcreteDecorator02(p1);
	p1 = new ConcreteDecorator03(p1);
	p1->show();
	cout << endl;

	Car *p2 = new ConcreteDecorator02(new Audi());
	p2->show();
	cout << endl;

	Car *p3 = new ConcreteDecorator03(new Benz());
	p3->show();
	cout << endl;

	return 0;
}