#include <iostream>

class Product
{
public:
    Product(double price) : price { price }
    {
    }

    virtual double total_price()
    {
        return price * 1.4;
    }
protected:
    double price;
};

class Fuel : public Product
{
public:

    Fuel(double price, double efficiency)
        : Product { price }, efficiency { efficiency }
    {
    }

    double total_price() override
    {
        return price * (1.2 + 0.1 / efficiency);
    }
private:
    double efficiency;
};

class Food : public Product
{
public:
    using Product::Product;
    double total_price() override
    {
        return price * 1.1 + 20.0;
    }
};

int main()
{
    Product coffee { 20.0 };
    Product pan { 199.0 };
    Fuel electricty { 2.0, 0.8 };
    Fuel petrol { 4.0, 0.5 };
    Food potato { 1.5 };
    Food tomato { 5.0 };

    std::cout << "Total prices: " << std::endl;
    std::cout << "coffee: " << coffee.total_price() << std::endl;
    std::cout << "pan: " << pan.total_price() << std::endl;
    std::cout << "electricty: " << electricty.total_price() << std::endl;
    std::cout << "petrol: " << petrol.total_price() << std::endl;
    std::cout << "potato: " << potato.total_price() << std::endl;
    std::cout << "tomato: " << tomato.total_price() << std::endl;
}