friend关键字使用之员工和经理类-C++

/*
功能：实现员工和经理类
作者：wind
日期：2013-11-08
*/
#include <iostream>
#include <string>
using namespace std;

int n=0,m=0;
class Manager;
//员工
class Employee
{
public:
	Employee(string iName=NULL,int iAge=NULL,int iYear=0,int iNum=0);
	~Employee(){};
	void printOn(Employee&);
	void retire();
   friend Manager;
private:
	string m_iName;
	int m_iAge;
	int m_iYear;
	int m_iNum;
};
//经理
class Manager:public Employee
{
public:
	Manager(string iName=NULL,int iAge=NULL,int iYear=0,int iNum=0,int ilevel = 0);
	~Manager(){};
	void printOn(Manager&);
	void retire();
private:
   int m_iLevel;

};

Employee::Employee(string iName,int iAge,int iYear,int iNum)
{
    m_iName=iName;
	m_iAge=iAge;
	m_iYear=iYear;
	m_iNum=iNum;
	n++;

}

Manager::Manager(string iName,int iAge,int iYear,int iNum,int ilevel)
{
	m_iName=iName;
	m_iAge=iAge;
	m_iYear=iYear;
	m_iNum=iNum;
	m_iLevel=ilevel;

}

void Employee::printOn(Employee&obj)
{
	cout<<obj.m_iName<<" "<<obj.m_iAge<<" "<<obj.m_iYear<<" "<<obj.m_iNum<<endl;
}


void Employee::retire()
{
	if (m_iAge>=55)
	{

		cout<<m_iName<<"超过了退休年龄，"<<m_iName<<"办理了退休手续"<<endl;
		n--;
	}
}

void Manager::printOn(Manager&obj)
{
	cout<<obj.m_iName<<" "<<obj.m_iAge<<" "<<obj.m_iYear<<" "<<obj.m_iNum<<endl;
}


void Manager::retire()
{
	if (m_iAge>=60)
	{

		cout<<m_iName<<"超过了退休年龄，"<<m_iName<<"办理了退休手续"<<endl;
		m--;
	}
}


int main(void)
{

	string name;
	int age;
	int year;
	int num;
	int level;
	int i=0;


	cout<<"请输入员工的姓名、年龄、工作年限和部门号:";
	cin>>name>>age>>year>>num;
	Employee a(name,age,year,num);

	cout<<"请输入员工的姓名、年龄、工作年限和部门号:";
	cin>>name>>age>>year>>num;
	Employee b(name,age,year,num);

    cout<<"请输入经理的姓名、年龄、工作年限和部门号、级别：";
	cin>>name>>age>>year>>num>>level;
   Manager c(name,age,year,num,level);

	cout<<"公司共有员工："<<n<<"人，"<<" 经理"<<m<<"人。";
	 a.retire();

     b.retire();
	 c.retire();
   cout<<"公司共有员工："<<n<<"人，"<<" 经理"<<m<<"人。";
	system("pause");
	return 0;
}