template program crashing during execution

Question

I'm implementing Doubly Linked List in C++, using templates. As I'm trying my hands on templates.

template <class T>
class DList{
    Node<T> *head;
    Node<T> *tail;
    public:
        Dlist(){
            head = tail = nullptr;
        }       
        void addToHead(T el){
            Node<T> *newNode = new Node<T>(el);
            if(head == nullptr){
                head = tail = newNode;
            }
            else{
                head -> prev = newNode;
                newNode -> next = head;
                head = newNode;
            }
        } };

When using this addToHead(), the if condition is not executing. And the program crashes.

Answer 1

They mistake was with the constructor function, it was just an typo. Because of which the head and tail pointers were not initializing and when the head pointer was compared against the nullptr in the if condition of the addToHead(), program was crashing.