#include <string>
#include <vector>
#include <iostream>

using namespace std;

// class C
struct Street
{
public:

    Street(string const& name, int residence_count)
        : name { name }, residence_count { residence_count }
    { }
    
    string get_name() const
    {
        return name;
    }

    int get_residence_count() const
    {
        return residence_count;
    }

    void increase_residence_count(int n)
    {
        residence_count += n;
    }
    
private:
    // Data member #1 in C
    string name;

    // Data member #2 in C
    int residence_count;
};

class City
{
public:

    // Constructor #1
    City(string const& name, Street const& street)
        : name{name}, streets { street }
    { }

    // Constructor #2
    City(string const& name, vector<Street> const& streets = {})
        : name{name}, streets { streets }
    { }

    void add_street(Street const& street)
    {
        streets.push_back(street);
    }

    // Takes a parameter and modifies the instance
    void increase_population(int amount)
    {
        int const per_street { amount / static_cast<int>(streets.size()) };
        for (Street& street : streets)
        {
            street.increase_residence_count(per_street);
        }
    }

    // performs some calculation without modifying the instance
    int get_population() const
    {
        int total { 0 };
        for (Street const& street : streets)
        {
            total += street.get_residence_count();
        }
        return total;
    }
    
private:

    // Data member #1 in B
    string name;

    // Data member #2 in B
    // STL container
    vector<Street> streets;
};

// testcases
int main()
{
    vector<Street> streets {
        Street{ "Universitetsvägen", 10000 },
        Street{ "Malmslättsvägen", 6000 },
        Street{ "Rydsvägen", 20000 }
    };

    {
        // Test const and calling a function on const object
        City const linkoping { "Linköping", streets };
        cout << linkoping.get_population() << endl;
    }

    {
        City linkoping { "Linköping", streets };

        // test all other member functions
        
        Street street { "Teknikringen", 0 };
        linkoping.add_street(street);
        
        linkoping.increase_population(4000);
        cout << linkoping.get_population() << endl;
    }
}