1.意图

    将对象组合成树形结构以表示“部分-整体”的层次结构。Composite使得用户对单个对象和组合对象的使用具有一致性。

2.动机

    可以组合多个简单组件以形成一些较大的组件，这些组件又可以组合成更大的组件。Composite模式描述了如何使用递归组合，使得用户不必对这些类进行区别。

3.适用性

• 表示对象的部分-整体层次结构。
• 希望用户忽略组合对象与单个对象的不同，用户将统一地使用组合结构中的所有对象。

4.结构

    

    5.代码实例

    

#include <memory>
#include <vector>

class Graphic
{
public:
    Graphic(std::shared_ptr<Graphic> pParent);
    virtual void Add(std::shared_ptr<Graphic>& pGraphic);
    virtual void Remove(std::shared_ptr<Graphic>& pGraphic);
    virtual std::shared_ptr<Graphic> GetChild(int iIndex);
    virtual std::shared_ptr<Graphic>& GetParent();
    virtual void Opereate();

protected:
    std::shared_ptr<Graphic> m_pParent;

    std::vector<std::shared_ptr<Graphic>> m_vecChildrenGraphics;

}; 

class Circle : public Graphic
{
public:
    Circle(std::shared_ptr<Graphic> pParent);
    void Opereate();
};


class Retangle : public Graphic
{
public:
    Retangle(std::shared_ptr<Graphic> pParent);
    void Opereate();
};


class Line : public Graphic
{
public:
    Line(std::shared_ptr<Graphic> pParent);
    void Opereate();
};

class Picture : public Graphic
{
public:
    Picture(std::shared_ptr<Graphic> pParent);
    virtual void Add(std::shared_ptr<Graphic>& pGraphic);
    virtual void Remove(std::shared_ptr<Graphic>& pGraphic);
    virtual std::shared_ptr<Graphic> GetChild(int iIndex);
    void Opereate();
};

#include "Graphic.h"
#include <iostream>


Graphic::Graphic(std::shared_ptr<Graphic> pParent) 
    : m_pParent(pParent)
{
}

 void Graphic::Add(std::shared_ptr<Graphic>& pGraphic)
 {
     std::cout<< "Leaf Cannot Add Childrren" << std::endl;
 }

 void Graphic::Remove(std::shared_ptr<Graphic>& pGraphic)
 {
     std::cout<< "Leaf Cannot Remove Childrren" << std::endl;
 }

 std::shared_ptr<Graphic> Graphic::GetChild(int iIndex)
 {
     std::cout<< "Leaf Cannot Get Child" << std::endl;
     return nullptr;
 }

 std::shared_ptr<Graphic>& Graphic::GetParent()
 {
     return m_pParent;
 }

 void Graphic::Opereate()
 {
     std::cout<< "Default Operate Executed" <<std::endl;
 }

 Circle::Circle(std::shared_ptr<Graphic> pParent)
     :Graphic(pParent)
 {
 }

 void Circle::Opereate()
 {
     std::cout << "Circle Operate Exeeuted" << std::endl;
 }

 Retangle::Retangle(std::shared_ptr<Graphic> pParent)
     :Graphic(pParent)
 {
 }

 void Retangle::Opereate()
 {
     std::cout << "Retangle Operate Exeeuted" << std::endl;
 }


  Line::Line(std::shared_ptr<Graphic> pParent)
     :Graphic(pParent)
 {
 }

 void Line::Opereate()
 {
     std::cout << "Line Operate Exeeuted" << std::endl;
 }


 Picture::Picture(std::shared_ptr<Graphic> pParent) 
    : Graphic(pParent)
{
}

 void Picture::Add(std::shared_ptr<Graphic>& pGraphic)
 {
     m_vecChildrenGraphics.push_back(pGraphic);

     std::cout<<