java - 我的 LinkedList 的 set 方法有什么问题

Question

我正在尝试实现一个链表。除了 set 方法之外，我的所有方法都有效。它只应该更改或替换给定索引处的元素。但是在索引中设置元素后，列表中的其余元素都为空，任何人都可以指出我在 set 方法中做错了什么吗？

        public class LArrayList<E> {

            private static class Node<E> {

                Node<E> next;

                E data;

                public Node(E dataValue) {
                    next = null;
                    data = dataValue;
                }

                @SuppressWarnings("unused")
                public Node(E dataValue, Node<E> nextValue) {
                    next = nextValue;
                    data = dataValue;
                }

                public E getData() {
                    return data;
                }

                public Node<E> getNext() {
                    return next;
                }

                public void setNext(Node<E> nextValue) {
                    next = nextValue;
                }
            }

            private Node<E> head;
            private static int listCount;

            public LArrayList() {

                head = new Node<>(null);
                listCount = 0;
            }

            public void add(int index, E e) throws IndexOutOfBoundsException{

                if (index < 0 || index >= listCount + 1) {

                    throw new IndexOutOfBoundsException("Bad index, please use index within range");
                }
                else{


                Node<E> positionTemp = new Node<>(e);
                Node<E> positionCurrent = head;

                for (int i = 0; i < index && positionCurrent.getNext() != null; i++) {
                    positionCurrent = positionCurrent.getNext();
                }

                positionTemp.setNext(positionCurrent.getNext());
                positionCurrent.setNext(positionTemp);
                listCount++;
            }
            }

            public E set(int index, E e) throws IndexOutOfBoundsException {

                if (index < 0 || index >= listCount) 
                    throw new IndexOutOfBoundsException("Bad index, please use index within range");


                Node<E> positionTemp = new Node<>(e);
                Node<E> positionCurrent = head;

                for (int i = 0; i < index; i++) {
                    positionCurrent = positionCurrent.getNext();
                }


                positionCurrent.setNext(positionTemp);

                return positionCurrent.getData();

            }

    public E get(int index) throws IndexOutOfBoundsException
    {

        if (index < 0 || index >= listCount)
            throw new IndexOutOfBoundsException("Bad index, please use index within range");

        Node<E> positionCurrent = head.getNext();
        for (int i = 0; i < index; i++) {
            if (positionCurrent.getNext() == null)
                return null;

            positionCurrent = positionCurrent.getNext();
        }
        return positionCurrent.getData();
    }



            public static void main(String[] args) {

                LArrayList<String> aa = new LArrayList<String>();
                aa.add(0, "0");
                aa.add(1, "1");
                aa.add(2, "2");
                aa.add(3, "3");
                aa.add(4, "4");
                aa.add(5, "5");


                System.out.println("The contents of AA are: " + aa);    

                 aa.set(0, "a");


                System.out.println("The contents of AA are: " + aa);    



                 System.out.println(aa.get(0));

                 System.out.println(aa.get(1));

                 System.out.println(aa.get(2));
                 System.out.println(aa.get(3));

                 System.out.println(aa.get(4));

                 System.out.println(aa.get(5));

        //OUTPUT IS: The contents of aa are: [0][1][2][3][4][5]
        //The contents of AA are: [a][b][c][d][e]
        //a
        //A
        //null
        //null
        //null
        //null

            }

        }

Answer 1

快速查看代码后:

 positionCurrent.setNext(positionTemp);

您不需要将 positionTemp 链接到它后面的元素吗？