add front(), rear()

realDuYuanChao · realDuYuanChao · commit 8fb8011845c6 · 2020-09-30T10:47:58.000+08:00
diff --git a/src/main/java/com/examplehub/datastructures/queue/Queue.java b/src/main/java/com/examplehub/datastructures/queue/Queue.java
@@ -79,6 +79,30 @@ public E dequeue() {
         return item;
     }
 
+    /**
+     * Get element at rear of this queue.
+     *
+     * @return element at rear of this queue.
+     */
+    public E rear() {
+        if (empty()) {
+            throw new IllegalStateException("Queue is empty");
+        }
+        return queue[rear];
+    }
+
+    /**
+     * Get element at front of this queue.
+     *
+     * @return element at front of this queue.
+     */
+    public E front() {
+        if (empty()) {
+            throw new IllegalStateException("Queue is empty");
+        }
+        return queue[front];
+    }
+
     /**
      * Clear all elements in the stack.
      */
diff --git a/src/test/java/com/examplehub/datastructures/queue/QueueTest.java b/src/test/java/com/examplehub/datastructures/queue/QueueTest.java
@@ -26,15 +26,15 @@ void testQueue() {
 
         assertEquals("1", queue.enqueue("1"));
         assertEquals("2", queue.enqueue("2"));
+        assertEquals("3", queue.front());
+        assertEquals("2", queue.rear());
         assertTrue(queue.full());
         assertEquals("[3, 4, 5, 1, 2]", queue.toString());
 
         assertEquals("3", queue.dequeue());
         assertEquals("4", queue.dequeue());
-        assertEquals("5", queue.dequeue());
-        assertEquals("1", queue.dequeue());
-        assertEquals("2", queue.dequeue());
 
+        queue.clear();
         assertEquals(queue.size(), 0);
         assertTrue(queue.empty());
         assertEquals("[]", queue.toString());
