简单的链表遍历问题

Question

我已经使用javascript实现了一个单独的链表。请找到以下代码：

class Node {
constructor(data) {
this.data = data;
this.nextElement = null;
}
}
class LinkedList {
constructor() {
this.head = null;
}
isEmpty() {
return this.head === null;
}
insertAtHead(data) {
const tempNode = new Node(data);
tempNode.nextElement = this.head;
this.head = tempNode;
}
traverse() {
let current = this.head;
while (current.nextElement != null) {
console.log("node data", current.data);
current = current.nextElement;
}
}
insertAtTail(data) {
const tempNode = new Node(data);
if (this.head === null) {
this.head = tempNode;
return;
}
let currentNode = this.head;
while (currentNode.nextElement != null) {
currentNode = currentNode.nextElement;
}
currentNode.nextElement = tempNode;
}
}
const linkedList = new LinkedList();
linkedList.insertAtTail(12);
linkedList.insertAtTail(23);
linkedList.insertAtTail(25);
linkedList.traverse();

但是遍历方法从不打印最后一个元素。我在这里错过了什么？insertAtTail方法看起来是正确的。有人能告诉我吗。

感谢

Answer 1

traverse在current.nextElement为null时停止循环——但此时current仍然是具有data的节点，只是它之后没有下一个节点。

相反，继续进行，直到节点本身是null:

traverse() {
let current = this.head;
while (current) { // *** Only change is on this line
console.log("node data", current.data);
current = current.nextElement;
}
}

(

while (current) {

可能是

while (current !== null) {

如果您愿意。(

实例：

class Node {
constructor(data) {
this.data = data;
this.nextElement = null;
}
}
class LinkedList {
constructor() {
this.head = null;
}
isEmpty() {
return this.head === null;
}
insertAtHead(data) {
const tempNode = new Node(data);
tempNode.nextElement = this.head;
this.head = tempNode;
}
traverse() {
let current = this.head;
while (current) {
console.log("node data", current.data);
current = current.nextElement;
}
}
insertAtTail(data) {
const tempNode = new Node(data);
if (this.head === null) {
this.head = tempNode;
return;
}
let currentNode = this.head;
while (currentNode.nextElement != null) {
currentNode = currentNode.nextElement;
}
currentNode.nextElement = tempNode;
}
}
const linkedList = new LinkedList();
linkedList.insertAtTail(12);
linkedList.insertAtTail(23);
linkedList.insertAtTail(25);
linkedList.traverse();

Answer 2

在遍历中，您需要检查所有节点，直到下一个节点为空。

所以我刚从遍历中删除了.nextElement，它运行得很好

class Node {
constructor(data) {
this.data = data;
this.nextElement = null;
}
}
class LinkedList {
constructor() {
this.head = null;
}
isEmpty() {
return this.head === null;
}
insertAtHead(data) {
const tempNode = new Node(data);
tempNode.nextElement = this.head;
this.head = tempNode;
}
traverse() {
let current = this.head;
while (current) { // Here
console.log("node data", current.data);
current = current.nextElement;
}
}
insertAtTail(data) {
const tempNode = new Node(data);
if (this.head === null) {
this.head = tempNode;
return;
}
let currentNode = this.head;
while (currentNode.nextElement != null) {
currentNode = currentNode.nextElement;
}
currentNode.nextElement = tempNode;
}
}
const linkedList = new LinkedList();
linkedList.insertAtTail(12);
linkedList.insertAtTail(23);
linkedList.insertAtTail(25);

linkedList.traverse();