#include <iostream>
#include <vector>

class Bacteria
{
public:
    
    Bacteria(double c)
        : nrOfBacteria{1},
          consumptionRate{c}
    {
    }
    
    virtual ~Bacteria() = default;
    
    virtual void update(double& nutrients) = 0;

    virtual void print(std::ostream& os) const = 0;
      
protected:
    
    int nrOfBacteria;
    double consumptionRate;
};

class Ecoli : public Bacteria
{
public:
    
    Ecoli(double c)
        : Bacteria(c)
    {
    }
    
    void update(double& nutrients) override
    {
        double delta { consumptionRate * nrOfBacteria };
        if(delta < nutrients)
        {
            nutrients -= delta;
            nrOfBacteria *= growthFactor;
            growthFactor *= growthRate;
        }
    }

    void print(std::ostream& os) const override
    {
        os << "E-coli count: " << nrOfBacteria
           << " with growth factor: " << growthFactor << std::endl;
    }
    
private:

    double growthFactor { 2.0 };
    double growthRate { 1.5 };
    
};

class Saureus : public Bacteria
{
public:
    
    Saureus(double c)
        : Bacteria(c)
    {
    }

    void update(double& nutrients) override
    {
        double delta { consumptionRate * nrOfBacteria };
        if(delta < nutrients)
        {
            nutrients -= delta;
            nrOfBacteria *= 3;
        }
    }

    void print(std::ostream& os) const override
    {
        os << "S-aureus count: " << nrOfBacteria << std::endl;
    }
};

class PetriDish
{
public:
    
    PetriDish(std::vector<Bacteria*> colonies, double nutrients)
        : colonies{colonies}, nutrients{nutrients}
    {
    }

    ~PetriDish()
    {
        for (Bacteria* bacteria : colonies)
        {
            delete bacteria;
        }
    }
    
    void simulate()
    {
        for (Bacteria* bacteria : colonies)
        {
            bacteria->update(nutrients);
        }
    }

    void print(std::ostream& os) const
    {
        for (Bacteria* bacteria : colonies)
        {
            bacteria->print(os);
        }
        os << "Nutrients: " << nutrients << std::endl;
    }

private:

    std::vector<Bacteria*> colonies;
    double nutrients;
};

int main()
{
    std::vector<Bacteria*> colonies { new Ecoli{1}, new Saureus{2} };
    
    PetriDish dish{colonies, 600};

    dish.print(std::cout);

    std::cout << "Simulating 5 time steps..." << std::endl;
    for(int i{}; i < 5; ++i)
    {
        dish.simulate();
    }

    dish.print(std::cout);
}