java - 在链表末尾添加节点(java)

Question

这是我的链表代码(不是主代码)。方法“addLast”给了我以下错误，我不知道如何解决它:“不能从静态上下文引用非静态变量”。它正在谈论这一行: return new Node(x,null);对于如何解决此问题，我将不胜感激。谢谢您

public class LinkedList
{

  private class Node 
    { 
        int item;
        Node link;

        public Node ()
        {
            item = Integer.MIN_VALUE;
            link = null;

        }

        public Node (int x, Node p)

        {  
            item = x;
            link = p;

        }

    } //End of node class


    private Node head;


    public LinkedList()
    {
        head = null;
    }

    //adds a node to the start of the list with the specified data
    //added node will be the first node in the list

    public void addToStart(int x)
    {
        head = new Node(x, head);
    }


    //adds a number at end of list 
    public static Node addLast(Node header, int x)
    { 
        // save the reference to the header so we can return it. 
        Node ret = header; 

        // check base case, header is null. 
        if (header == null) { 
            return new Node(x, null); 
        } 

        // loop until we find the end of the list 
        while ((header.link != null)) { 
            header = header.link; 
        } 

        // set the new node to the Object x, next will be null. 
        header.link = new Node(x, null); 
        return ret; 
    }


    //displays the list
    public void printList()
    {
        Node position = head;
        while(position != null)
        {
            System.out.print(position.item + " ");
            position = position.link;
        }

        System.out.println();
    }
}

Answer 1

这里有两个解决方案:

使 Node 成为静态嵌套类:

private static class Node { ... }

或者，将 addLast 方法设置为实例方法:

public Node addLast(Node header, int x) { ... }