C++ virtual function sample

#include<iostream>
using namespace std;


class Employee{
    private:
 
    protected:    
      int base_salary;  
    public:
         
           Employee()
           {
              //cout<< "hello!"<< endl;
              base_salary = 24000;    
           }        
           virtual void calculateSalary()=0;  
   
};

class Manager : public  Employee
{
    protected:
       int Manager_salary;    
    public:
         
       void calculateSalary()
       {
          Manager_salary = base_salary + 30000;
          cout << "Manager Salary :" << Manager_salary << endl;
       }        
   
   
   
};

class Staff : public   Employee
{
    protected:
       int Staff_salary;    
    public:
         
       void calculateSalary()
       {
          Staff_salary = base_salary + 10000;
          cout << "Staff Salary :" << Staff_salary << endl;
       }        
   
   
   
};



int main()
{

  Manager obj;
  obj.calculateSalary();
  Staff obj_1;
  obj_1.calculateSalary();


   
 system("PAUSE");
    return 0;  
}