#include <iostream>
#include <iterator>
#include <set>
#include <string>
#include <vector>

struct Is_Positive
{
    bool check(int const& value)
    {
        return value > 0;
    }
};

class Has_Length
{
public:
    
    Has_Length(int size)
        : size { size }
    { }
    
    bool check(std::string const& str)
    {
        return str.size() >= size;
    }
    
private:
    
    int size;
};

class Constrained_Container
{
public:

    using Condition = Is_Positive;
    using value_type = int;
    
    Constrained_Container(Condition condition)
        : condition { condition }
    { }

    bool insert(value_type value)
    {
        if (condition.check(value))
        {
            container.insert(container.end(), value);
            return true;
        }
        return false;
    }

    value_type const& get(unsigned index) const
    {
        return *(std::next(container.begin(), index));
    }
    
    unsigned size() const
    {
        return container.size();
    }

private:


    Condition condition;
    std::vector<int> container;
    
};

int main()
{
    // Skriv om detta testfall så att det fungerar för din kod
    std::cout << "==== vector:" << std::endl;
    { // Ska skriva ut: 9 3 4 
        Is_Positive condition;
        Constrained_Container v { condition };
        v.insert(-5);
        v.insert(0);
        v.insert(-1);
        v.insert(9);
        v.insert(3);
        v.insert(-2);
        v.insert(4);
        
        for (unsigned i { 0 }; i < v.size(); ++i)
        {
            std::cout << v.get(i) << " ";
        }
        std::cout << std::endl;
    }

    /* För G och VG
    std::cout << "==== set:" << std::endl;
    { // Ska skriva ut: framfor typename value_type 
        Has_Length condition { 4 };
        Constrained_Container<std::set<std::string>, Has_Length> s { condition };
        s.insert("value_type");
        s.insert("ska");
        s.insert("ha");
        s.insert("typename");
        s.insert("framfor");

        for (unsigned i { 0 }; i < s.size(); ++i)
        {
            std::cout << s.get(i) << " ";
        }
        std::cout << std::endl;
    }
    */

    /* För VG
    std::cout << "vector till set:" << std::endl;
    { // Ska skriva ut: 0.5 2.3
        std::vector<double> values { -4.5, 2.3, -1.2, 0.5 };
        Is_Positive<double> condition { };
        Constrained_Container<std::set<double>, Is_Positive<double>> s { values.begin(), values.end(), condition };

        for (unsigned i { 0 }; i < s.size(); ++i)
        {
            std::cout << s.get(i) << " ";
        }
        std::cout << std::endl;
    }
    */
}