gistfile1.cpp

class ListNode {
    friend class List;
public:
    ListNode* nextNodePointer;
    ListNode* previousNodePointer;
    int value;

private:
    /**
    * Constructs an empty element of the list, points to NULL by default
    */
    ListNode();

    /**
     * Constructs an element of the list, points to NULL by default
     */
    ListNode(const int _value);
};

void List::clear() {
    if (firstNodePointer != NULL) {
        ListNode* nodeToDelete = firstNodePointer;
        ListNode* nextNodeToDelete = firstNodePointer->nextNodePointer;

        while (nextNodeToDelete != NULL) {
            delete nodeToDelete;
            nodeToDelete = nextNodeToDelete;
            nextNodeToDelete = nextNodeToDelete->nextNodePointer;
        }

        delete lastNodePointer;

        rewriteFirstNodePointer(NULL);
        rewriteLastNodePointer(NULL);
    }
}