大话设计模式-组合模式

组合模式

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

适用场景：需求中体现部分与整体层次的结构时，以及希望用户可以忽略组合对象与单个对象的不同，统一地使用组合结构中的所有对象。

//company.h

#pragma once
#include <string>
#include <list>
#include <iostream>
using namespace  std;
class Company{
protected:
    string name;
public:
    Company(string name):name(name){}
    virtual void add(Company *c)=0;
    virtual void remove(Company *c)=0;
    virtual void display(int depth)=0;
    virtual void lineOfDuty()=0;
};

class ConcreteCompany:public Company{
private:
    list<Company*> *listCom;
public:
    ConcreteCompany(string name):Company(name){
        listCom = new list<Company*>;
    };
    void add(Company *c){
        listCom->push_back(c);
    }
    void remove(Company *c){
        listCom->remove(c);
    }
    void display(int depth){
        cout << string(depth,'-') << name << endl;
        list<Company*>::iterator it;
        for(it=listCom->begin();it!=listCom->end();it++){
            (*it)->display(depth+2);
        }
    }

    void lineOfDuty(){
        list<Company*>::iterator it;
        for(it=listCom->begin();it!=listCom->end();it++){
            (*it)->lineOfDuty();
        }
    }
    ~ConcreteCompany(){
        cout << "~ConcreteCompany"<< endl;
        delete listCom;
    }
};

class HRDepartment :public Company{
public:
    HRDepartment(string name):Company(name){

    }

    void add(Company *c){}
    void remove(Company *c){}
    void display(int depth){
        cout << string(depth,'-')  << name<<endl;
    }
    void lineOfDuty(){
        cout << name << "员工招聘培训管理" << endl;
    }
    ~HRDepartment(){
        cout << "~HRDepartment()" << endl;
    }
};

class FinanceDepartment :public Company{
public:
    FinanceDepartment(string name):Company(name){

    }

    void add(Company *c){}
    void remove(Company *c){}
    void display(int depth){
        cout <<  string(depth,'-')  << name<<endl;
    }
    void lineOfDuty(){
        cout << name << "公司财务收支管理" << endl;
    }
    ~FinanceDepartment(){
        cout << "~FinanceDepartment()" << endl;
    }
};

//main.cpp

#include <iostream>
#include <cstring>
#include <stdlib.h>
#include "company.h"

using namespace std;

int main(){
    ConcreteCompany *root = new ConcreteCompany("北京总公司");
    HRDepartment *hd = new HRDepartment("总公司人力资源部");
    FinanceDepartment *fd = new FinanceDepartment("总公司财务部");

    root->add(hd);
    root->add(fd);

    ConcreteCompany *com = new ConcreteCompany("武汉分公司");
    HRDepartment *whd = new HRDepartment("武汉分公司人力资源部");
    FinanceDepartment *wfd = new FinanceDepartment("武汉分公司财务部");
    com->add(whd);
    com->add(wfd);

    root->add(com);

    root->display(1);

    root->lineOfDuty();

    delete wfd;
    delete whd;
    delete com;
    delete fd;
    delete hd;
    delete root;
    return 0;
}