Design mode 9-Combination Mode

In the combination mode, the whole and part can be viewed in the same way. The base class sets a node interface to derive leaf nodes and non-leaf nodes. Leaf nodes cannot be added. Non-leaf nodes can be added to form a typical tree structure.

The combination mode is widely used in the rendering tree of the game engine.

Composite. H Content

 1 #ifndef Composite_H_H 2 #define Composite_H_H 3  4 #include<iostream> 5 #include<vector> 6 using namespace std; 7  8 class Composite 9 {10 public:11     Composite(string str) : name(str) {}12     virtual ~Composite() {}13     virtual void add(Composite *composite) = 0;14     virtual void display() = 0;15 protected:16     string name;17 };18 19 class Leaf : public Composite20 {21 public:22     Leaf(string str) : Composite(str) {}23     virtual void add(Composite *composite) {}24     virtual void display() { cout << name << " "; }25 private:26 27 };28 29 class Component : public Composite30 {31 public:32     Component(string str) : Composite(str) { }33     virtual void add(Composite *composite) { vecChildren.push_back(composite); }34     virtual void display(){35         cout << name << " " << endl;36         for(size_t i=0; i<vecChildren.size(); ++i){37             vecChildren[i]->display();38         }39     }40 private:41     vector<Composite*> vecChildren;42 };43 44 void CompositeTest()45 {46     Composite *com1 = new Component("A");47     Composite *leaf1 = new Leaf("B");48     Composite *leaf2 = new Leaf("C");49     com1->add(leaf1);50     com1->add(leaf2);51 52     Composite *com2 = new Component("D");53     Composite *leaf4 = new Leaf("E");54     Composite *leaf5 = new Leaf("F");55     com2->add(leaf4);56     com2->add(leaf5);57 58     com1->add(com2);59 60     com1->display();61 62 }63 64 #endif

Design mode 9-Combination Mode