Generic List Items

#include <list>
#include <string>
#include <memory>
#include <cstdio>

class IParameter {
public:
    virtual ~IParameter() = default;
};

template<typename T>
class Parameter : public IParameter{
private:
    T value;

public:
    T GetValue() {
        return value;
    }
    explicit Parameter(T value) : value(value) {}
    ~Parameter() override = default;
};

class Context {
 private:
    std::list<std::unique_ptr<IParameter>> list;

 public:
    template<typename P>
    void Add(P p) {
        list.push_back(std::make_unique<Parameter<P>>(Parameter<P>(p)));
    }

    template<typename P>
    P Get(int index) const {
        unsigned N = index;/* index of the element you want to retrieve */
        if (list.size() > N) {
            auto iterator = std::next(list.begin(), N);// 'it' points to the element at index 'N'
            auto ptr = iterator->get();
            auto value = (Parameter<P>*) (ptr);
            return value->GetValue();
        }
    }
};

int main() {
    Context context;
    context.Add<std::string>("Text string");
    context.Add<int32_t>(32);

    printf("Item: %i \n", context.Get<int32_t>(1));
    printf("Item: %s \n", context.Get<std::string>(0).c_str());
}