class Code
{
public:
    Code(std::list<CodeWord> collection)
    {
        iter = collection.begin();
        end = collection.end();
    }

    CodeWord *operator>>()
    {
        if(iter == end)
            return null;
        CodeWord *c = *iter;
        iter++;
        return c;
    }

private:
    std::list<CodeWord>::iterator iter;
    std::list<CodeWord>::iterator end;
}