这个打印矩阵的程序的错误在哪里？

Question

import java.util.*;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class WordSearch {

public WordSearch() {

}

public void getMatrix() throws FileNotFoundException {



    File file = new File("/home/cameron/Desktop/words");

    ArrayList<String> words = new ArrayList<String>();

    String largest = "";

    char[][] data;

    int col = 0;




    Scanner sc = new Scanner(file);


    while (sc.hasNextLine()) {


        String first = sc.nextLine();

        words.add(first);


        if(first.length()>largest.length()){



         largest=first;

         col=largest.length();

        }
    }



        data = new char[col][col];

        int curWord=0;


        for(int i=0; i<words.size(); i++){
            String word=words.get(curWord);  
            int start=0;
            int row=0;
            int choice=0;
            int index=0;


         do
         {

           start = (int)(Math.random()*data.length);
           row =  (int)(Math.random()*data.length);
           choice = (int)(Math.random()*2);

         }
         while(start+word.length()>data.length);



         index=0;

         if(choice==0){
             for(int j=start; j<start+word.length(); j++){              
                 if(data[row][j]==0 || data[row][j]==word.charAt(index)){
                     data[row][j] = word.charAt(index);

                     index++;
                 }

                 else{ i=0; continue;}


             }
         }

         if(choice==1){
             for(int j=start; j<start+word.length(); j++){
                 if(data[j][row]==0 || data[j][row]==word.charAt(index)){
                    data[j][row] = word.charAt(index);

                    index++;
                 }

                 else{ i=0; continue;}
             }
         }

           curWord++;
          }



       for(int i=0; i<data.length; i++){
         for(int j=0; j<data[i].length; j++){
            if(data[i][j]==0)
             System.out.print("A ");
            else    
             System.out.print(data[i][j]+" ");
         }

         System.out.println();
        }


    }


 public static void main(String[] args) throws FileNotFoundException {



    WordSearch check = new WordSearch();

    check.getMatrix();

 }
}  

我设置了一个if else语句，用于如果单词的字符要打印在不同字符或单词的顶部，那么for循环(do while上方的循环）将重新启动，以确保单词被正确打印出来。

不过我有个问题。该程序似乎工作了大约50%，并打印出如下内容：

A A h A A A A f A 
A A a A A l A e A 
A A m A A a A n A 
A A b A A d A c A 
A A u A A y A e A 
A A r A A b A A A 
A A g A A u A A A 
A A e A A g A A A 
A A r A A A A A A 

偶尔我会得到这个错误，而且只是这个错误（在这个特定的索引处）：

Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 3, Size: 3
at java.util.ArrayList.rangeCheck(ArrayList.java:653)
at java.util.ArrayList.get(ArrayList.java:429)
at WordSearch.getMatrix(WordSearch.java:59)
at WordSearch.main(WordSearch.java:132)

编辑：以下是从文件中读入程序的内容：

ladybug
hamburger
fence

Answer 1

好了，为了便于可读性和重用，我将for循环中的常见逻辑提取到一个方法中，对代码进行了一点清理。另外，else条件会给您带来一个问题，通过将“i”重置回0并导致偶尔的错误，这是不必要的。

请尝试这个修改的代码，让我知道如果你继续得到一个错误。在连续运行大约20次后，我不再看到问题：

    import java.util.*;
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.util.Scanner;

    public class WordSearch {
        ArrayList<String> words = new ArrayList<>();

        private void getMatrix(String filePath) throws FileNotFoundException {
            File file = new File(filePath);
            String largest = "";
            char[][] data;
            int col = 0;
            Scanner sc = new Scanner(file);

            while (sc.hasNextLine()) {
                String first = sc.nextLine();
                words.add(first);

                if(first.length() > largest.length()){
                    largest = first;
                    col = largest.length();
                }
            }

            data = new char[col][col];
            int curWord = 0;

            for(int i = 0; i < words.size(); i++){
                String word = words.get(curWord);
                int start = 0;
                int row = 0;
                int choice = 0;

                do{
                    start = (int)(Math.random()*data.length);
                    row =  (int)(Math.random()*data.length);
                    choice = (int)(Math.random()*2);
                }
                while(start + word.length() > data.length);

                updateData(choice, start, row, word, data);
                curWord++;
            }

            for (char[] aData : data) {
                for (char anAData : aData)
                    if (anAData == 0)
                        System.out.print("A ");
                    else
                        System.out.print(anAData + " ");
                System.out.println();
            }
        }

        private void updateData(int choice, int start, int row, String word, char[][] data){

            for(int index = 0, j = start; j < start + word.length(); j++){
                switch(choice){
                    case 0:
                        if(data[row][j] == 0 || data[row][j] == word.charAt(index)){
                            data[row][j] = word.charAt(index);
                            index++;
                        }
                        break;
                    case 1:
                        if(data[j][row] == 0 || data[j][row] == word.charAt(index)){
                            data[j][row] = word.charAt(index);
                            index++;
                        }
                        break;
                }
            }
        }

        private String getRandomLetter(){
            Random r = new Random();
            char c = (char) (r.nextInt(26) + 'a');
            return ("" + c).toUpperCase();
        }

        public static void main(String[] args) throws FileNotFoundException {
            WordSearch check = new WordSearch();
            check.getMatrix("/home/cameron/Desktop/words");
        }
    }  

程序很整洁，做得很好。为了让它更有趣一点，我添加/更改了一些东西，您可以根据自己的喜好使用或不使用这些东西。

words.add(first.toUpperCase());

K M D X H A L B H 
C M L G A W N F F 
M V W Z M D T O T 
L A D Y B U G T Y 
Y J U J U R D V C 
C I C O R P P I L 
B B P R G R Q L X 
D B D V E X R V K 
E I J H R G L D B