组合设计模式，就是可以把多个类组合在一个大类中，形成一个树形结构。

#include <set>
#include <iostream>
#include <string>
using namespace std;

class Coporate
{
protected:
	string name;
	set<Coporate *> coporate;

public:
	explicit Coporate(string n = "", string d = "") : name(n), coporate() {}

	virtual string getName()
	{
		return name;
	}

	virtual void add(Coporate *c)
	{
		coporate.insert(c);
	}

	virtual void show()
	{
		set<Coporate *>::iterator it = coporate.begin();
		for ( ; it != coporate.end(); it++)
		{
			(*it)->show();
		}
	}

	virtual void remove(Coporate *c)
	{
		coporate.erase(c);
	}
};

class VicePresident : public Coporate
{
	string division;
public:
	explicit VicePresident(string n = "", string d = "")
	{
		name = n;
		division = d;
	}

	virtual void show()
	{
		cout<<"Vice President's Name is : "<<name
			<<"; In Division: "<<division<<endl;//关键处
	}
};

class Division : public Coporate
{
public:
	explicit Division(string n = "")
	{
		name = n;
	}
};

class Coporation : public Coporate
{
public:
	Coporation() {}
};

int main()
{
	Coporation corp;

	Division sale("Sales Department");
	VicePresident vp1("Jelly", sale.getName());
	VicePresident vp2("Kelly", sale.getName());
	sale.add(&vp1);
	sale.add(&vp2);

	Division tech("Technique Department");
	VicePresident vp3("Qilly", tech.getName());
	VicePresident vp4("Melly", tech.getName());
	tech.add(&vp3);
	tech.add(&vp4);

	VicePresident vp("Billy", "At large");
	corp.add(&vp);

	corp.add(&sale);
	corp.add(&tech);

	corp.show();

	return 0;
}