java - Java 中的数组排序 soicanpost

Question

我的问题是如何对 arrayofnames 和 arrayofdownloads 进行排序，以便它们按升序排列，并且每个名称与其相应的下载数量相匹配。我已经尝试了 4 个小时，但我似乎无法理解它

谢谢

    import java.util.*;
import java.util.stream.*;

public class short6 
{ 
    public static void main(String[] args) 
    {
        String[] arrayofnames = new String[4];
        int[] arrayofdownloads = new int[4];

        printmessage(arrayofnames, arrayofdownloads);
        details(arrayofnames, arrayofdownloads);
        System.exit(0);
    }

    public static void printmessage(String[] arrayofnames, int[] arrayofdownloads)
    {
        Scanner scanner = new Scanner(System.in);
        int totalDownloads = 0;

        for (int i = 0; i < arrayofnames.length; i++) 
        {
            System.out.println("What is track " + (i + 1));
            arrayofnames[i] = scanner.nextLine();
            System.out.println("How many thousands of times has it been downloaded? ");
            arrayofdownloads[i] = Integer.parseInt(scanner.nextLine());
        }

        Arrays.sort(arrayofnames);
        Arrays.sort(arrayofdownloads);

        System.out.println("The track downloaded the most is " + arrayofdownloads[0]+".");
    }

    public static void details(String[] arrayofnames, int[] arrayofdownloads)
    {
        int totaldownloads = IntStream.of(arrayofdownloads).sum();
        System.out.println("The track downloaded the most is " + arrayofdownloads[0]+".");
        System.out.println("The total number of downloads of these 4 tracks was " + totaldownloads * 1000 +".");

        System.out.println("\nThe details of the downloads are");

        for (int i = 1; i < arrayofnames.length; i++) 
        {
            System.out.println(arrayofnames[i]);
            System.out.println((arrayofdownloads[i]));
        }
    }
}

Answer 1

我将开始创建一个包含歌曲名称和下载次数的歌曲(例如)类:

public class Song {

  private String name;

  private int downloads;

  public Song(String name, int downloads) {
    this.name = name;
    this.downloads = downloads;
  }

  public String getName() {
    return this.name;
  }

  public int getDownloads() {
    return this.downloads;
  }

}

然后，创建歌曲数组:

Song[] arrayOfSongs = new Song[4];

并从输入加载它:

arrayOfSongs[i] = new Song(scanner.nextLine(), Integer.parseInt(scanner.nextLine()));

现在您只需使用比较器对其进行排序:

Arrays.sort(arrayOfSongs, new Comparator<Song> () {
            public int compare(Song o1, Song o2) {
                // Sorting by name              
                return o1.getName().compareTo(o2.getName());
            }

        });

或者，正如 @Benoit 在评论中所说，这样会更容易(Java 8 或更高版本):

Arrays.sort(arrayOfSongs, Comparator.comparing(Song::getName));

大功告成，只需打印对象(toString 方法在这里会很有帮助)，您就可以对信息进行排序。

编辑:要读取编写问题的输入，您只需将值存储在变量中，例如

System.out.println("What is track " + (i + 1));
String songName = scanner.nextLine();
System.out.println("How many thousands of times has it been downloaded? ");
int songDownloads = Integer.parseInt(scanner.nextLine());
arrayOfSongs[i] = new Song(songName, songDownloads);

或者您可以在 Song 类中实现 setter 方法并创建一个不带参数的构造函数，这样您就可以在读取值时设置它们。