Абстрактные методы

#include <iostream>
#include <iomanip>
using namespace std;
class Employee {
public:
    Employee(double value = 12792) : mrot(value) {}
    virtual ~Employee() {}
    virtual double salary()const {
        return mrot;
    }
protected:
    double mrot;
};
class Manager : virtual public Employee {
public:
    Manager(double a, double p) : a(a), p(p) {}
    double salary()const override {
        auto s = mrot * a;
        return s += s * p;
    }
private:
    double a;
    double p;
};
class Administrator : virtual public Employee {
public:
    Administrator(double a) : a(a) {}
    double salary()const override {
        return mrot * a;
    }
private:
    double a;
};
class Programmer : virtual public Employee {
public:
    Programmer(double a, double p, double x) : a(a), p(p), x(x) {}
    double salary()const override {
        auto s = mrot * a;
        return s += s * p + s * x;
    }
private:
    double a;
    double p;
    double x;
};
unsigned quantity(const char* msg) {
    cout << msg;
    unsigned value;
    cin >> value;
    cin.ignore(cin.rdbuf()->in_avail());
    return value;
}
int main() {
    Manager manager(6.5, 0.25);
    Administrator administrator(4.8);
    Programmer programmer(8.25, 0.15, 0.2);
    auto managers = quantity("Managers: ");
    auto administrators = quantity("Administrators: ");
    auto programmers = quantity("Programmers: ");
    auto budget
        = manager.salary() * managers
        + administrator.salary() * administrators
        + programmer.salary() * programmers;
    cout << "Budget: " << fixed << setprecision(2) << budget << '\n';
    system("pause > nul");
}