如何在Java中对文本文件进行冒泡排序

Question

How do I properly bubble sort through a text file by assigning the values to an array. In the code below I tried to assign the values from the text file to a string while there is still something to fetch. Then I used a for loop to assign the one that I have fetch to the array. Then tried to use the bubble sort to hopefully sort the numbers that I have fetch from highest to lowest. But I get this one as an output:

5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  
10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  10  
4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  4  
20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  20  
100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  100  
0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  
78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  78  
12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  12  
29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  29  

Here's my code:

     try{
 int i;
 String ss;
   FileReader fr;
      fr = new FileReader (new File("X:\\file.txt"));
      BufferedReader br = new BufferedReader (fr);


while ((ss = br.readLine()) != null) {
    String[] sv = ss.split(" ");


        String splayer_name=sv[1];
        String s_player_score=sv[2];

 for(int xy=0;xy<player_name.length;xy++){
        player_name[xy]=splayer_name;
        player_score[xy]=Integer.parseInt(s_player_score);
}


bubble_srt(player_score, player_score.length);

    for(i = 0; i <player_score.length; i++)
      System.out.print(player_score[i]+"  ");
    System.out.println();




  }

  }catch(Exception e){}

Please help,

update: someone asked about the file structure, are you referring to this one: This is the file.txt, the one that I'm fetching is the rightmost number:

1 a 5
2 b 10
5 x 4
7 h 20

Answer 1

I think your main problem is with the loop:

 for(int xy=0;xy<player_name.length;xy++){
        player_name[xy]=splayer_name;
        player_score[xy]=Integer.parseInt(s_player_score);
}

Every time you read in a line. You are replacing the entire contents of the *player_name* array with the splayer_name, and the the entire contents of the *player_score* with the int value of s_player_score.

I am guessing that what you are trying to do is add a single new entry to player_name and player-score. The size of the two arrays have to be equal to the number of rows in the text file, so you might want to use some form of List rather than an array.

For both the storage arrays (or Lists) add the name once and the score once and I think that will get you well on the way to what you are trying to do.

Answer 2

1. Move the for loop & the bubble_srt() call outside the while loop. You are replacing the entire contents on each iteration like what the earlier answer has correctly pointed out. You only want to sort AFTER the entire file contents are read.

2. Since your file can be of any size there is no way to initialize the array beforehand unless you want to perform two reads one to get the count and then to read into the array. You would be better off using a List. Here's a skeleton code:

    try { int i; String ss; FileReader fr; fr = new FileReader(new File("file.txt")); BufferedReader br = new BufferedReader(fr); int xy=0; List<String> player_name = new ArrayList<String>(); List<Integer> player_score = new ArrayList<Integer>(); 
    while ((ss = br.readLine()) != null) { String[] sv = ss.split(" "); player_name.add(sv[1]); player_score.add(Integer.parseInt(sv[2])); } bubble_srt(player_score); 
   \n\n} catch (Exception e) { \n} \n

(Modify your bubble sort to take a list input)