Ошибка "Нельзя создать экземпляр абстрактного класса"

#pragma once
#include<iostream>
#include"Sex.h"
 
using namespace std;
 
class Worker
{
private:
 
protected:
    string typeWorker;
    string _fullName;
    Sex _sex;
public:
    Worker(string name, Sex sex);
    void setName(string name);
    string getName() const;
    void setSex(Sex sex);
    Sex getSex() const;
    string getTypeWorker() const;
    virtual void work(float sizeWork) = 0;
    //virtual float pay() { return 0; }
    virtual float pay() = 0; 
};

#include "Worker.h"
 
Worker::Worker(string name, Sex sex)
{
    setName(name);
    setSex(sex);
}
 
void Worker::setName(string name)
{
    if (name != "")
        _fullName = name;
}
 
string Worker::getName() const
{
    return _fullName;
}
 
void Worker::setSex(Sex sex)
{
    if (sex >= Sex(0) && sex <= Sex(3))
        _sex = sex;
}
 
Sex Worker::getSex() const
{
    return _sex;
}
 
string Worker:: getTypeWorker() const
{
    return typeWorker; 
}

#include "WorkerHours.h"
 
WorkerHours::WorkerHours(string typeWorker, string fullName, Sex sex, float payment, float overPayment, float normalHours):Worker(fullName, sex)
{
    typeWorker = "WorkerHours";
    setPayment(payment);
    setOverPayment(overPayment);
    setNormalHours(normalHours);
    _finalHours = 0;
}
 
void WorkerHours::setPayment(float payment)
{
    if (payment > 0)
        _payment = payment;
}
 
float WorkerHours::getPayment() const
{
    return _payment;
}
 
void WorkerHours::setOverPayment(float overPayment)
{
    if (overPayment >= 0)
    _overPayment = overPayment;
}
 
float WorkerHours::getOverPayment() const
{
    return _overPayment;
}
 
void WorkerHours::setNormalHours(float normalHours)
{
    if (normalHours > 0)
    _normalHours = normalHours;
}
 
float WorkerHours::getNormaHours() const
{
    return _normalHours;
}
 
float WorkerHours::getFinalHours() const
{
    return _finalHours;
}
 
void WorkerHours::work(float sizeWork) 
{
    if(sizeWork>=0)
    _finalHours += sizeWork;
}
 
float WorkerHours::pay()
{
    float sum = _payment*_normalHours;
    if (_finalHours > _normalHours) {
        float dop=_finalHours-_normalHours;
        sum += (dop * _overPayment);
    }
    _finalHours = 0;
 
    return sum;
}

#include "WorkerCommiss.h"
 
WorkerCommiss::WorkerCommiss(string typeWorker, string fullName, Sex sex, float staticPayment, float percent) :Worker(fullName, sex)
{
    typeWorker = "WorkerCommiss";
    setStaticPayment(staticPayment);
    setPercent(percent);
    _sells = 0;
}
 
void WorkerCommiss::setStaticPayment(float staticPayment)
{
    if (staticPayment > 0)
        _staticPayment = staticPayment;
}
 
float WorkerCommiss::getStaticPayment() const
{
    return _staticPayment;
}
 
void WorkerCommiss::setPercent(float percent)
{
    if (percent > 0 && percent <= 100)
        _percent = percent;
}
 
float WorkerCommiss::getPercent() const 
{
    return _percent;
}
 
float WorkerCommiss::getSells() const
{
    return _sells;
}
 
void WorkerCommiss::work(float sizeWork)
{
    if(sizeWork>=0)
    _sells += sizeWork;
}
 
float WorkerCommiss::pay()
{
    float _final=_staticPayment;
    _final += (_sells * _percent);    
    _sells = 0;
    return _final;
}