//An example of a simple double linked list using OOP techniques#includeusing namespace std; struct Node{ double value; Node *N,*P; Node(double y) { value = y; N = P = NULL; }}; class doubleLinkedList{ Node *front; Node *back; public: doubleLinkedList() { front = NULL; back = NULL; } ~doubleLinkedList(){ destroyList();} void appendNodeFront(double x); void appendNodeBack(double x); void dispNodesForward(); void dispNodesReverse(); void destroyList();}; void doubleLinkedList::appendNodeFront(double x) { Node *n = new Node(x); if( front == NULL) { front = n; back = n; } else { front->P = n; n->N = front; front = n; } } void doubleLinkedList::appendNodeBack(double x) { Node *n = new Node(x); if( back == NULL) { front = n; back = n; } else { back->N = n; n->P = back; back = n; } } void doubleLinkedList::dispNodesForward() { Node *temp = front; cout << "\n\nNodes in forward order:" << endl; while(temp != NULL) { cout << temp->value << " " ; temp = temp->N; } } void doubleLinkedList::dispNodesReverse() { Node *temp = back; cout << "\n\nNodes in reverse order :" << endl; while(temp != NULL) { cout << temp->value << " " ; temp = temp->P; } }void doubleLinkedList::destroyList(){ Node *T = back; while(T != NULL) { Node *T2 = T; T = T->P; delete T2; } front = NULL; back = NULL;}int main(){ doubleLinkedList *list = new doubleLinkedList(); //append nodes to front of the list for( int i = 1 ; i < 4 ; i++) list->appendNodeFront(i*1.1); list->dispNodesForward(); list->dispNodesReverse(); //append nodes to back of the list for( int i = 1 ; i < 4 ; i++) list->appendNodeBack(11.0 - (1.1 * i)); cout << endl << endl; list->dispNodesForward(); list->dispNodesReverse(); cout << endl << endl; delete list; return 0;} /* Program's outputNodes in forward order:3.3 2.2 1.1 Nodes in reverse order :1.1 2.2 3.3 Nodes in forward order:3.3 2.2 1.1 9.9 8.8 7.7 Nodes in reverse order :7.7 8.8 9.9 1.1 2.2 3.3*/