Нет доступа к функции

// Employee.h
 
#ifndef EMPLOYEE_H_INCLUDED
#define EMPLOYEE_H_INCLUDED
 
 
class Employee {
public:
    virtual double averageFixedSalary(double value) { // эта функция
        return value;
    }
};
 
 
 
#endif // !EMPLOYEE_H_INCLUDED

// FixedEmployee.h
 
#ifndef FIXEDEMPLOYEE_H_INCLUDED
#define FIXEDEMPLOYEE_H_INCLUDED
 
#include <string>
#include "Employee.h"
 
class FixedEmployee : Employee {
public:
    FixedEmployee(int __id, std::string __name, int __salary) { 
        this->id = __id;
        this->name = __name;
        this->salary = __salary;
    }
 
 
private:
    int id;
    int salary;
    std::string name;
};
 
#endif // !FIXEDEMPLOYEE_H_INCLUDED

// main.cpp
 
#include <iostream>
#include <conio.h>
#include "FixedEmployee.h"
 
 
int main(int argc, char *argv []) {
    FixedEmployee first(1, "name", 100);
    std::cout << first.averageFixedSalary(100); //  error C2247: нет доступа к "Employee::averageFixedSalary", поскольку "FixedEmployee" использует "private" для наследования из "Employee"
 
    _getch();
}