How to realize the Decoration pattern of C++ Design pattern

In this article, the editor introduces in detail "how to realize the decoration pattern of C++ design pattern". The content is detailed, the steps are clear, and the details are handled properly. I hope that this article "how to realize the decoration pattern of C++ design pattern" can help you solve your doubts.

The decorative pattern is a classical class function extension mode, whose essence is that the decorative class uses inheritance and aggregation to obtain the interface and the object to be implemented, and then implements the extended interface by itself.

Action

The decoration pattern dynamically appends responsibility to the object through the decoration class. if you want to expand the function, you can expand the new function of the object without adding subclasses through inheritance, which provides a more flexible alternative than inheritance. it avoids the bloated system caused by the expansion of the number of subclasses.

Code implementation

Class Component {public: Component () {} virtual ~ Component () {} virtual void operation () = 0; class ConcreteComponentA: public Component {public: ConcreteComponentA () {} ~ ConcreteComponentA () {} void operation () {fprintf (stderr, "ConcreteComponentA's operation!\ n");}}; class ConcreteComponentB: public Component {public: ConcreteComponentB () {} ~ ConcreteComponentB () {fprintf (stderr, "ConcreteComponentB's operation!\ n");} Class Decorator: public Component {public: Decorator (): mComponent (NULL) {} virtual ~ Decorator () {} virtual void operation () {if (mComponent) mComponent- > operation ();} virtual void setComponent (Component* pComponent) {mComponent = pComponent;} protected: Component* mComponent;}; class ConcreteDecoratorE: public Decorator {public: ConcreteDecoratorE (); virtual ~ ConcreteDecoratorE (); virtual void addBehavior () {mComponent- > operation () Fprintf (stderr, "ConcreteDecoratorE's addBehavior!\ n");}}; class ConcreteDecoratorF: public Decorator {public: ConcreteDecoratorF (); virtual ~ ConcreteDecoratorF (); virtual void addBehavior () {operation (); fprintf (stderr, "ConcreteDecoratorF's addBehavior!\ n");}}; int main () {ConcreteComponentB * pComponent = new ConcreteComponentB (); ConcreteDecoratorF decorator; decorator.setComponent (pComponent); decorator.addBehavior () } after reading this, the article "how to realize the Decoration pattern of C++ Design pattern" has been introduced. If you want to master the knowledge of this article, you still need to practice and use it before you can understand it. If you want to know more about related articles, welcome to follow the industry information channel.