组合模式，顾名思义，通过组合关系定义类间的关联关系，实现了将对象组合成树形结构，最终实现类的复用。可能是由于设计模式看的多了，初看组合模式的类图，感觉和装饰者模式类图很相似，都是使用继承和组合关系，当然，也只是结构相似而已。

#include <iostream>
#include <vector>
using namespace std;class Component {
public:virtual void Operation() { }virtual void Add(const Component& com) { }virtual void Remove(const Component& com) { }virtual Component* GetChild(int index) {return 0;}virtual ~Component() { }
};class Composite :public Component {
public:void Add(Component* com) {_coms.push_back(com);}void Operation() {for (auto com : _coms)com->Operation();}void Remove(Component* com) {//_coms.erase(&com);}Component* GetChild(int index) {return _coms[index];}private:std::vector<Component*> _coms;
};class Leaf :public Component {
public:void Operation() {cout << "Leaf::Operation..." << endl;}
};int main() {Leaf *leaf = new Leaf();leaf->Operation();Composite *com = new Composite();com->Add(leaf);com->Operation();Component *leaf_ = com->GetChild(0);leaf_->Operation();delete leaf;delete com;return 0;
}