C++设计模式——组合模式

组合模式(Composite)：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

 

 

 

 

 

 

#include<iostream>
#include<list>
using namespace std;
//公司类... 抽象或者接口
class Company {
public:
    Company(string name) {
        this->name = name;
    }
    virtual void Add(Company* c) = 0; //增加
    virtual void Remove(Company* c) = 0;//移除
    virtual void Display(int depth) = 0;//显示
    virtual void LineOfDuty() = 0;//履行职责...不同部分履行的职责不一样
protected:
    string name;
};

//具体公司类  树枝节点
class ConcreteCompany :public Company {
public:
    ConcreteCompany(string name) :Company(name) {}

    virtual void Add(Company* c) {
        children->push_back(c);
    }
    virtual void Remove(Company* c) {
        children->remove(c);
    }
    virtual void Display(int depth) {
        string  s(depth, '-');
        cout << s << name << endl;
        for (list<Company*>::iterator it = children->begin(); it != children->end(); it++) {
            (*it)->Display(depth + 2);
        }
    }
    virtual void LineOfDuty() {
        for (list<Company*>::iterator it = children->begin(); it != children->end(); it++) {
            (*it)->LineOfDuty();
        }
    }

private:
    list<Company*>* children = new list<Company*>;
};

//叶子节点  人力资源部
class HRDepartment :public Company {
public:
    HRDepartment(string name) :Company(name) {}

    virtual void Add(Company* c) {}
    virtual void Remove(Company* c) {}
    virtual void Display(int depth) {
        string  s(depth, '-');
        cout << s << name << endl;
    }
    virtual void LineOfDuty() {
        cout << name << " 员工招聘培训管理" << endl;
    }
};

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

    virtual void Add(Company* c) {}
    virtual void Remove(Company* c) {}
    virtual void Display(int depth) {
        string  s(depth, '-');
        cout << s << name << endl;
    }
    virtual void LineOfDuty() {
        cout << name << " 公司财务收支管理" << endl;
    }
};

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

    ConcreteCompany* comp = new ConcreteCompany("上海华东分公司");
    comp->Add(new HRDepartment("华东分公司人力资源部"));
    comp->Add(new FinanceDepartment("华东分公司财务部"));
    root->Add(comp);

    ConcreteCompany* comp1 = new ConcreteCompany("南京办事处");
    comp1->Add(new HRDepartment("南京办事处人力资源部"));
    comp1->Add(new FinanceDepartment("南京办事处财务部"));
    comp->Add(comp1);

    ConcreteCompany* comp2 = new ConcreteCompany("杭州办事处");
    comp2->Add(new HRDepartment("杭州办事处人力资源部"));
    comp2->Add(new FinanceDepartment("杭州办事处财务部"));
    comp->Add(comp2);

    cout << "结构图: " << endl;
    root->Display(1);

    cout << "\n职责图: " << endl;
    root->LineOfDuty();

    delete comp2;
    delete comp1;
    delete comp;
    delete root;
    return 0;
}

 

 

 

 应用场景：

需求中是体现部分与整体层次的结构时， 以及你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时，就应该考虑使用组合模式