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

 1 #pragma once
 2 #include <string>
 3 #include <list>
 4 #include <iostream>
 5 using namespace  std;
 6 class Company{
 7 protected:
 8     string name;
 9 public:
10     Company(string name):name(name){}
11     virtual void add(Company *c)=0;
12     virtual void remove(Company *c)=0;
13     virtual void display(int depth)=0;
14     virtual void lineOfDuty()=0;
15 };
16 
17 class ConcreteCompany:public Company{
18 private:
19     list<Company*> *listCom;
20 public:
21     ConcreteCompany(string name):Company(name){
22         listCom = new list<Company*>;
23     };
24     void add(Company *c){
25         listCom->push_back(c);
26     }
27     void remove(Company *c){
28         listCom->remove(c);
29     }
30     void display(int depth){
31         cout << string(depth,'-') << name << endl;
32         list<Company*>::iterator it;
33         for(it=listCom->begin();it!=listCom->end();it++){
34             (*it)->display(depth+2);
35         }
36     }
37 
38     void lineOfDuty(){
39         list<Company*>::iterator it;
40         for(it=listCom->begin();it!=listCom->end();it++){
41             (*it)->lineOfDuty();
42         }
43     }
44     ~ConcreteCompany(){
45         cout << "~ConcreteCompany"<< endl;
46         delete listCom;
47     }
48 };
49 
50 class HRDepartment :public Company{
51 public:
52     HRDepartment(string name):Company(name){
53 
54     }
55 
56     void add(Company *c){}
57     void remove(Company *c){}
58     void display(int depth){
59         cout << string(depth,'-')  << name<<endl;
60     }
61     void lineOfDuty(){
62         cout << name << "员工招聘培训管理" << endl;
63     }
64     ~HRDepartment(){
65         cout << "~HRDepartment()" << endl;
66     }
67 };
68 
69 class FinanceDepartment :public Company{
70 public:
71     FinanceDepartment(string name):Company(name){
72 
73     }
74 
75     void add(Company *c){}
76     void remove(Company *c){}
77     void display(int depth){
78         cout <<  string(depth,'-')  << name<<endl;
79     }
80     void lineOfDuty(){
81         cout << name << "公司财务收支管理" << endl;
82     }
83     ~FinanceDepartment(){
84         cout << "~FinanceDepartment()" << endl;
85     }
86 };

//main.cpp

 1 #include <iostream>
 2 #include <cstring>
 3 #include <stdlib.h>
 4 #include "company.h"
 5 
 6 using namespace std;
 7 
 8 int main(){
 9     ConcreteCompany *root = new ConcreteCompany("北京总公司");
10     HRDepartment *hd = new HRDepartment("总公司人力资源部");
11     FinanceDepartment *fd = new FinanceDepartment("总公司财务部");
12 
13     root->add(hd);
14     root->add(fd);
15 
16     ConcreteCompany *com = new ConcreteCompany("武汉分公司");
17     HRDepartment *whd = new HRDepartment("武汉分公司人力资源部");
18     FinanceDepartment *wfd = new FinanceDepartment("武汉分公司财务部");
19     com->add(whd);
20     com->add(wfd);
21 
22     root->add(com);
23 
24     root->display(1);
25 
26     root->lineOfDuty();
27 
28     delete wfd;
29     delete whd;
30     delete com;
31     delete fd;
32     delete hd;
33     delete root;
34     return 0;
35 }