Update stack and queue.

codes/java/chapter_stack_and_queue/deque.java

@@ -10,7 +10,7 @@ import java.util.*;
 
 public class deque {
     public static void main(String[] args) {
-        /* 初始化队列 */
+        /* 初始化双向队列 */
         Deque<Integer> deque = new LinkedList<>();
 
         /* 元素入队 */
@@ -19,7 +19,7 @@ public class deque {
         deque.offerLast(4);
         deque.offerFirst(3);
         deque.offerFirst(1);
-        System.out.println("队列 deque = " + deque);
+        System.out.println("双向队列 deque = " + deque);
 
         /* 访问队首元素 */
         int peekFirst = deque.peekFirst();
@@ -33,11 +33,12 @@ public class deque {
         int pollLast = deque.pollLast();
         System.out.println("队尾出队元素 pollLast = " + pollLast + "，队尾出队后 deque = " + deque);
 
-        /* 获取队列的长度 */
+        /* 获取双向队列的长度 */
         int size = deque.size();
-        System.out.println("队列长度 size = " + size);
+        System.out.println("双向队列长度 size = " + size);
 
-        /* 判断队列是否为空 */
+        /* 判断双向队列是否为空 */
         boolean isEmpty = deque.isEmpty();
+        System.out.println("双向队列是否为空 = " + isEmpty);
     }
 }