Question

What is the current syntax for writing a template member class parameter inside a template class.

This is what I been trying to do:

template <class T>
    class Node
    {
    public:
        Node(); // constructor 
        Node(const Node<T> &);           // copy constructor 
        ~Node();             // destructor
        T value;
        Node *next;
    };


template <class T> 
class Linked_list
{
public:
    Linked_list(); // constructor 
    Linked_list(const Linked_list<T> &); // copy constructor 
    ~Linked_list();             // destructor
    T pop();
    void push(T value);
    T top();
    bool is_empty();
    void clear();

private:
    Node<T> *head; // COMPILER ERROR
};

Why this is a compiler error?

Node<T> *head; // COMPILER ERROR

Answer 1

Perhaps when you call:

Node<T> *head;

T is not an object type, and it doesn’t know how to construct that. Try:

Node<std::string> *head;

or something like that. T is not an object type, it is just like a variable name, except it is actually a variable type within the class Node and LinkedList.