java - 附加到 Java 中的链表

Question

代码编译并运行，但 addToEnd 方法不起作用，这对我来说似乎是正确的，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

这是我的其他课程的代码

 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);
}
    }

标签： javalinked-listsingly-linked-list

Answer 1

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，所以您需要遍历整个列表，然后添加newNode到末尾（我相信您已经理解了）。为此，只需继续设置current为current.getNext()until current.getNext()is null，然后调用current.setNext(newNode);

Node next;

while ((next = current.getNext()) != null) {
    current = next;
}

current.setNext(newNode);