1. 第一种情况下循环队列中共有25个元素: (rear - front + max)%max = (48 - 23 + 60) % 60 = 25 第二种情况下共有35个元素: (rear - front + max)%max = (23 - 48 + 60) % 60 = 35 2. 判断空: rear == front 3. 判断满: (rear+1)%max == front