在Java中添加到链表
在Java中添加到链表
提问于 2018-09-30 07:28:11
代码可以编译并运行，但addToEnd方法不起作用，在我看来似乎是正确的，但我不确定错误在哪里，有人可以指导我需要修复代码的内容或位置吗
下面是我的另一个类的代码
public class LinkedList {
private Node head;
/**
* constructor
* pre: none
* post: A linked list with a null item has been created.
*/
public LinkedList() {
head = null;
}
/**
* Activity: finds size of the Linked List.
* Pre-Condition: none
* Post-Condition: The size of the list is returned
*/
public int size() {
int counter = 0;
Node current = head;
while(current != null) {
counter++;
current = current.getNext();
}
return counter;
}
/**
* Adds a node to the end of the linked list.
* pre: String parameter
* post: The linked list has a new node at the end.
*/
public void addAtEnd(String s) {
Node current = head;
Node newNode = new Node(s);
if(head == null) {
head = newNode;
head.setNext(null);
}
else {
while(current.getNext() == null) {
current.setNext(newNode);
current = newNode;
}
}
}
private class Node {
private String data;
private Node next;
/**
* constructor
* pre: none
* post: A node has been created.
*/
public Node(String newData) {
data = newData;
next = null;
}
/**
* The node pointed to by next is returned
* pre: none
* post: A node has been returned.
*/
public Node getNext() {
return(next);
}
/**
* The node pointed to by next is changed to newNode
* pre: none
* post: next points to newNode.
*/
public void setNext(Node newNode) {
next = newNode;
}
/**
* The node pointed to by next is returned
* pre: none
* post: A node has been returned.
*/
public String getData() {
return(data);
}
}
}这是我的主类代码，Blume和Dahl从未被添加到列表中：
public class LinkedListDemo {
public static void main(String[] args) {
LinkedList list = new LinkedList();
list.addAtFront("Sachar");
list.addAtFront("Osborne");
list.addAtFront("Suess");
System.out.println("List has " + list.size() + " items.");
System.out.println(list);
list.addAtEnd("Blume");
list.addAtEnd("Dahl");
System.out.println(list);
}
}回答 3
Stack Overflow用户
回答已采纳
发布于 2018-09-30 07:36:45
public void addAtEnd(String s) {
Node current = head;
Node newNode = new Node(s);
if(head == null) {
head = newNode;
head.setNext(null);
}
else {// problem is here. You need to find the node that has getNext()==null,
//so you need to loop all nodes where get next != null
while(current.getNext() == null) {
current.setNext(newNode);
current = newNode;
}
}更改为此
else{
//iterate to the last node
while(current.getNext() != null) {
current = current.getNext();
}
//Append the new node to the end
current.setNext(newNode);
}Stack Overflow用户
发布于 2018-09-30 07:36:08
while (current.getNext() == null) {
current.setNext(newNode);
current = newNode;
}这是不正确的；因为您没有跟踪列表的尾部，所以需要遍历整个列表，然后在末尾添加newNode (我相信您已经理解了这一点)。为此，只需将current设置为current.getNext()，直到current.getNext()为null，然后调用current.setNext(newNode);
Node next;
while ((next = current.getNext()) != null) {
current = next;
}
current.setNext(newNode);Stack Overflow用户
发布于 2018-09-30 07:39:03
public void addAtEnd(String s) {
Node current = head;
Node newNode = new Node(s);
if(current == null) {
head = newNode;
} else {
while(current.getNext() != null) {
current = current.getNext();
}
current.setNext(newNode);
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52573356
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