Question

因此，我有一个使用提供的节点类的自定义linkedList（单个）类。

现在我有另一个类来QuickSort这个。（为了简洁起见，我只想专注于编辑L.head）

但是，我不想将quicksort方法传递给整个linkedList，而是将其从链表中传递给头部。

我的问题是访问此头节点并从quckSort方法/类更改它，我不想删除它或只是更改元素值

主：

public class TestLinkedList {
    public static <E extends Comparable<E>> void main(String[] args) {
        MyLinkedList<Integer> L = new MyLinkedList<Integer>();
        L.add(3);
        L.add(1);
        L.add(2);
        System.out.println("Initial=" + L);
        MySort.quickSort(L.head);
        System.out.println("After  ="+L);
    }
}

快速排序：

public class MySort {
    public static <E extends Comparable<E>> void quickSort(MyNode<E> list) {

        list = list.next;
    }

节点类：

public class MyNode<E extends Comparable<E>> {
    E element;
    MyNode<E> next;

    public MyNode(E item) {
        element = item;
        next = null;
    }
}

LinkedList类：

public class MyLinkedList<E extends Comparable<E>> {

    public MyNode<E> head;

    /**
     * Default constructor
     */
    public MyLinkedList() {
        this.head = new MyNode<E>(null);
    }

    /**
     * Adds given element to MylinkedList
     * 
     * @param e
     *            Given element to be added
     */
    public void add(E e) {
        assert e != null : "Violation of: e is not null";

        MyNode<E> temp = new MyNode<E>(e);

        if (head.element != null) {
            temp.next = head;
            head = temp;
        } else {
            this.head = temp;
        }
    }

    /**
     * Given a certain element, will try to locate and return whether it exists
     * in the MylinkedList
     * 
     * @param e
     *            Element being searched for
     * @return Result Result of whether this MyLinkedList contains the given
     *         Element
     */
    public boolean find(E e) {
        assert e != null : "Violation of: e is not null";

        boolean result = false;
        MyNode<E> temp = head;

        outerloop: while (temp.element != null && temp.next != null) {
            if (temp.element.equals(e)) {
                result = true;
                break outerloop;
            }
            temp = temp.next;
        }
        return result;
    }

    /**
     * Inserts given element before specific element
     * 
     * @param e
     *            Element being inserted before
     * @param e2
     *            Element being inserted
     */
    public void insertElementBefore(E e1, E e2) {
        assert e1 != null : "Violation of: e1 is not null";
        assert e2 != null : "Violation of: e2 is not null";
        MyNode<E> temp = head;
        MyNode<E> prev = head;
        MyNode<E> newElement = new MyNode<E>(e2);

        outerloop: while (temp.element != null && temp.next != null) {
            if (temp.element.equals(e1)) {
                prev.next = newElement;
                newElement.next = temp;
                break outerloop;
            }
            prev = temp;
            temp = temp.next;
        }
    }

    /**
     * Deletes given element from MylinkedList
     * 
     * @param e
     *            Element being deleted
     */
    public void delete(E e) {
        assert e != null : "Violation of: e is not null";

        MyNode<E> temp = head;
        MyNode<E> prev = head;

        loop: while (temp.element != null) {
            if (temp.element.equals(e)) {
                if (temp == head) {
                    head = temp.next;
                } else {
                    prev.next = temp.next;
                }
                break loop;
            }
            prev = temp;
            temp = temp.next;
        }
    }

    /**
     * Overridden toString; prints out all elements cleanly
     */
    public String toString() {
        String result = "\"";
        MyNode<E> temp = head;

        loop: while (temp.element != null) {
            result += temp.element + " ";
            if (temp.next != null) {
                temp = temp.next;
            } else {
                break loop;
            }
        }
        return result + "\"";
    }
}

Answer 1

在java中，参数按值传递。也就是说，您无法通过在本地方法中更改引用的地址来修改引用的地址。我建议你做的是让QuickSort（）方法返回下一个Node地址。

从另一个类访问特定的类变量

1 个答案: