inhertance

#include <iostream>
#include<string>
using namespace std;
int sum=0;
class emp
{
    string name;
    int payrate;
public:
    emp(){
        payrate=0;
        name = "NO NAME";
    }
    void set_emp()
    {
        cout<<"Enter employee name : ";cin>>name;
        cout<<"Enter employee pay rate : ";cin>>payrate;
        sum+=payrate;
    }
    void get_emp()
    {
        cout<<"employee name : "<<name<<endl;
        cout<<"employee pay rate : "<<payrate<<endl;
    }
    void calc()
    {
        float av;
        av = sum /4;
        cout<<"The employee pay rate is : "<<av<<endl;
    }
};
class manager:public emp
{
    string position,duties;
public:
    manager()
    {
        position = duties = "KNOWN";
    }
    void set_m()
    {
        cout<<"Enter manager position : ";cin>>position;
        cout<<"Enter manager duties : ";cin>>duties;
    }
    void get_m()
    {
        cout<<"manager position : "<<position<<endl;
        cout<<"manager duties : "<<duties<<endl;
    }
};
int main()
{
    emp e[4];
    for(int i=0;i<4;i++)
    {
        e[i].set_emp();
    }
    e[0].calc();
    manager m;
    return 0;
}