java - 将项目添加到列表后打印链表的内容

Question

如何在向列表添加项后打印链表的内容？

我编写了链表，我尝试在链表中间添加一个值。添加后还得看链表的内容。

我该怎么做？

代码如下:

public class LinkedList {
    int item;
    LinkedList next;

    public LinkedList()  // null constructor 
    { }

    // constructor to add pass the item and next value
    public LinkedList(int item,LinkedList next) 
    {
        this.item= item;
        this.next= next;
    }

    // constructor for items with null reference ie. the last element
    public LinkedList(int item) 
    {
        this(item,null);
    }

    // inserting an item in the linkedlist
    // (this assigns old reference to the new items next)
    public void additem(int item) 
    {
        this.next = new LinkedList(item,next);
    }

    public static void main(String args[])
    {
        LinkedList l1 = new LinkedList();
        LinkedList l2 = new LinkedList();
        LinkedList l3 = new LinkedList();
        LinkedList l4 = new LinkedList();
        l1.item = 3;
        l1.next = l2;
        l2.item = 5;
        l2.next = l3;   
        l3.item = 7;
        l3.next = l4;
        l4.item = 9;
        l4.next = null;

        System.out.println(l1);

        // inserting an item after l1 (so l1 points to the newly added value 
        // and the new one gets the nxt items refernce)
        l1.additem(8);
    }
}

代码中可能会有一些错误。如果我错了，请纠正我。

Answer 1

看到您需要更改您的 additem 类并定义一个遍历方法。

add item方法需要传入旧节点，之后要插入新节点，返回旧节点重新赋值。

必须手动从一个元素遍历到另一个元素的遍历方法。

public static LinkedList additem(LinkedList l1,int item) //inserting an item in the linkedlist (this assigns old reference to the new items next)
{
LinkedList l2=new LinkedList(item,l1.next);
l1.next = l2;
return l1;

}

public static void traverse( LinkedList l1){
    do{
        System.out.println(l1.item);
        if(l1.next!=null){
            l1=l1.next;
        }
    }while(l1.next!=null);
     System.out.println(l1.item);
}

public static void main(String args[])
{
    LinkedList l1 = new LinkedList();
    LinkedList l2 = new LinkedList();
    LinkedList l3 = new LinkedList();
    LinkedList l4 = new LinkedList();
    l1.item = 3;
    l1.next = l2;
    l2.item = 5;
    l2.next = l3;   
    l3.item = 7;
    l3.next = l4;
    l4.item = 9;
    l4.next = null;

    //traverse(l1);

    l1=additem(l1,8); // inserting an item after l1 (so l1 points to the newly added value and the new one gets the nxt items refernce)
     traverse(l1);
}

输出:3个8个5个79