C++ variant template

variant.cpp

#include <memory>
#include <string>

class variant
{
public:

    template <class T>
    variant& operator = (T const& t)
    {
        typedef type<T> assign_type;
        object = std::auto_ptr<assign_type>(new assign_type(t));
        return *this;
    }

    template <class T>
    operator T ()
    {
        typedef type<T> assign_type;
        assign_type& type = dynamic_cast<assign_type&>(*object);
        return type.get();
    }

private:

    class base
    {
    public:

        virtual ~base() {}
    };

    typedef std::auto_ptr<base> base_ptr;

    template <class T>
    class type : public base
    {
    public:

        type(T const& t)
        : object(t)
        {
        }

        T get() const
        {
            return object;
        }

    private:

        T object;
    };

    base_ptr object;
};

struct dummy
{
    int a;
    int b;
    int c;
};

int main()
{
    variant v1, v2, v3, v4;

    v1 = 2;
    v2 = 5.0f;
    v3 = std::string("Pot of gold");
    v4 = dummy();

    int         i = v1;
    float       f = v2;
    std::string s = v3;
    dummy       d = v4;

    return 0;
}