什么是以下两个C ++类之间的区别？

    //Version 1
    template <typename T>
    class Node<T> {
        private:
            T data;
            Node *next;
        public:
            Node(T data) {
                this->data = data;
                this->next = NULL;
            }
    };


    //Version 2
    template <typename T>
    class Node {
        private:
            T data;
            Node *next;
        public:
            Node(T);
    };
    template <typename T>
    Node<T>::Node(T val) {
        data = val;
        next = NULL;
    }
    //Version 1
    template <typename T>
    c