[数据结构与算法]双链表的简单实现和测试（Java）

1.初始化节点

package linkedlist;

public class BookNode {
    public int id;
    public String name;
    public double price;

    public BookNode pre;
    public BookNode next;

    @Override
    public String toString() {
        return "BookNode{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                '}';
    }

    public BookNode(int id, String name, double price) {
        this.id = id;
        this.name = name;
        this.price = price;
    }
}

2.初始化链表及简单操作

package linkedlist;

import jdk.nashorn.internal.ir.IfNode;

public class LinkedList {
    // 头结点
    BookNode node = new BookNode(0, "", 0.0);

    /**
     * 在链表尾添加新的节点
     */
    public void add(BookNode bookNode) {
        BookNode temp = node;
        while (true) {
            if (temp.next == null) {
                break;
            }
            temp = temp.next;
        }

        temp.next = bookNode;
        bookNode.pre = temp;

    }

    /**
     * 修改节点
     */
    public void update(BookNode bookNode) {
        // 判断非空
        if (node.next == null) {
            System.out.println("此链表为空");
            return;
        }

        boolean flag = false;
        BookNode temp = node;
        while (true) {
            if (temp.id == bookNode.id) {
                break;
            }
            if (temp == null) {
                flag = true;
                break;
            }

            temp = temp.next;
        }

        if (flag) {
            System.out.println("链表中没有该节点");
        } else {
            temp.name = bookNode.name;
            temp.price = bookNode.price;
        }


    }

    /**
     * 根据id删除元素
     *
     * @param id
     */
    public void del(int id) {
        // 判断非空
        if (node.next == null) {
            System.out.println("此链表为空");
        }
        boolean flag = false;
        BookNode temp = node;
        while (true) {
            if (temp.id == id) {
                break;
            }
            if (temp.next == null) {
                flag = true;
                break;
            }

            temp = temp.next;
        }

        if (flag) {
            System.out.println("链表中没有此元素");
        } else {
            temp.pre.next = temp.next;
            if (temp.next != null) {
                temp.next.pre = temp.pre;
            }

        }


    }


    /**
     * 遍历元素
     */
    public void list() {
        // 判断非空
        if (node.next == null) {
            System.out.println("此链表为空");
            return;
        }
        BookNode temp = node.next;
        while (true) {
            if (temp == null) {
                break;
            }
            System.out.println(temp);
            temp = temp.next;
        }
    }


}

3.简单测试

package linkedlist;

public class LinkedListTest {
    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        BookNode bookNode1 = new BookNode(1, "a", 66);
        BookNode bookNode2 = new BookNode(2, "b", 66);
        BookNode bookNode3 = new BookNode(3, "c", 66);
        BookNode bookNode4 = new BookNode(4, "d", 66);

        list.list();

        // 添加
        list.add(bookNode1);
        list.add(bookNode2);
        list.add(bookNode3);
        list.add(bookNode4);
        //list.list();

        // 删除
        list.del(1);
        list.list();

        // 修改
        list.update(new BookNode(2, "aaa", 666666));
        list.list();
    }
}