So this linked list happened to be circular, but it could also have been terminated by using a next pointer value of 0 -- the null value -- which would indicate we've reached the end of the list.

所以这个链表恰好是循环的，但它也可以通过使用 next 指针值 0——空值——来终止，这表明我们已经到达了链表的末尾。