import java.util.Scanner;

public class AircraftInventory {

class Node {

   Aircraft v;
   Node prev;
   Node next;

   public Node(Aircraft v) {
         set(v);
   }

   public Node() {
         set(null);
   }

   public Aircraft get() {
         return this.v;
   }

   public void set(Aircraft v) {
         this.v = v;
   }

}

Node head;
Node tail;
Integer n;

Node recent;
int recentIndex;

public AircraftInventory(Integer n) {
   this.n = n;
   head = new Node();
   Node current = head;
   for (int i = 1; i < n; i++) {
         current.next = new Node();
         current.next.prev = current;
         current = current.next;
   }
   tail = current;
   recent = head;
   recentIndex = 0;
}

public AircraftInventory() {
   n = 10;
   head = new Node();
   Node current = head;
   for (int i = 1; i < n; i++) {
         current.next = new Node();
         current.next.prev = current;
         current = current.next;
   }
   tail = current;
   recent = head;
   recentIndex = 0;
}

public Aircraft get(int index) {
   while (recentIndex != index) {
         if (recentIndex < index) {
            recent = recent.next;
            recentIndex++;
         } else if (recentIndex > index) {
            recent = recent.prev;
            recentIndex--;
         }
   }
   return recent.get();
}

public void put(Aircraft value, int index) {
   if (index >= n) {
         Node current = tail;
         while (index >= n) {
            current.next = new Node();
            current.next.prev = current;
            current = current.next;
            n++;
         }
         tail = current;
   }
   while (recentIndex != index) {

         if (recentIndex < index) {
            recent = recent.next;
            recentIndex++;
         } else if (recentIndex > index) {
            recent = recent.prev;
            recentIndex--;
         }
   }
   recent.set(value);
}

public void insert(Aircraft value, int index) {
   if (index >= n) {
         Node current = tail;
         while (index >= n) {
            current.next = new Node();
            current.next.prev = current;
            current = current.next;
            n++;
         }
         tail = current;
   }
   while (recentIndex != index) {
         if (recentIndex < index) {
            recent = recent.next;
            recentIndex

4.14 Ch 4 Program: Drawing a half arrow (Java) This program output...