Question

我删除双向链表的播放器的代码工作正常，但System.out.print语句不适用。我在removeFirst和removeLast之前放置了System.outs.print语句，因为我不知道输出在节点中删除的数据的方法，所以在删除之前将其打印出来。我知道我目前的方法设计不好，但我不确定使用什么功能。

我在if语句中检查哪些条件以查看节点是否已成功删除？

    else if (mChoice.startsWith("4")) {
    System.out.println("What do you want to delete?");

    mChoice = in.nextLine();

    if (mChoice.contains("first")) {
       System.out.println("Removed first player " + rBook.mHead.getData());
       rBook.removeFirst();
    }

    else if (mChoice.contains("last")) {
       System.out.println("Removed last player " + rBook.mHead.mPrev.getData());
       rBook.removeLast();
    }

    else {

       rBook.remove(rBook.searchByName(mChoice));

       // System.out.println(rBook.get() + " removed.");  this line

    }

Answer 1

我建议您修改remove()函数以返回刚删除的元素。所以您正在查看的代码如下：

Player deleted = rBook.remove(rBook.searchByName(mChoice));
System.out.println(deleted.get() + " removed.");

Answer 2

如果要存储列表中的哪些元素已被删除（例如，稍后打印或取消删除它们），那么更好的设计将是

仅将这些元素标记为已删除，或
将他们转移到另一个历史＆＃34;列表。

哪种解决方案更好取决于您要解决的问题。

Answer 3

如果您不想更改您的Player类及其功能，请尝试以下操作：

    else if (mChoice.startsWith("4")) {
    System.out.println("What do you want to delete?");

    mChoice = in.nextLine();
    Player deleted;
    if (mChoice.contains("first")) {
       deleted = rBook.mHead.getData();
       rBook.removeFirst();
       System.out.println("Removed first player " + deleted);
    }

    else if (mChoice.contains("last")) {
       deleted = rBook.mHead.mPrev.getData();
       rBook.removeLast();
       System.out.println("Removed last player " + deleted );

    }

    else {
       deleted = rBook.searchByName(mChoice);
       rBook.remove(searchByName(mChoice));
       System.out.println(deleted + " removed.");

    }

双向链接列表输出已删除的元素

3 个答案: