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Thread: Reading ints into a multidimensional array

  1. #1
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    Default Reading ints into a multidimensional array

    My problem occurs during the for loops to read in the values from the file into my scores array. The program reads in and prints the first 6 values or 2 lines of ints, but then I get ArrayIndexOutOfBoundsException: 2

    I have no idea why this is stopping there. If I have j<1000, it will read 17 values. Anyway, the file I'm reading in is below (wasn't sure the formatting for a text file).

    Any help would be appreciated

    Andy Matt Tom
    3 2 3
    4 4 5
    3 3 2
    2 2 2
    2 4 2
    2 3 2
    4 4 5
    2 3 3
    4 3 5
    3 3 6
    2 2 5
    3 3 3
    3 3 2
    3 2 4
    3 2 6
    3 4 3
    2 3 2
    2 2 2
    50 52 62


    import java.io.*;
    import java.util.*;
     
    public class Calc
    {
     
        public static void main( String args[] )
        {
    		try
    		{
     
    		if (args.length<1)
    		{
    			System.out.printf("\n...You must enter the name of a file\n");
    			System.exit(0);
    		}
     
    		Scanner infile  = new Scanner ( new File(args[0]) );
     
     
    		int par= 3;
    		int play= 18;
    		String[] players= new String[play];
    		int k=0;
    		int scores[][]= new int[play-1][par-1];
     
    		while(infile.hasNext())
    		{
    		players[k]=infile.next();
     
    		k++;
     
    		if (k==play)
    		break;
    		}
     
     
    		for(int j=0; j<par; j++)
    		{
    			for (int i=0; i<play; i++)
    			{
    			scores[j][i]=infile.nextInt();
    			System.out.println(scores[j][i]);
    			}
     
    		}
     
    		}
    		catch (FileNotFoundException e)
    		{
    		System.out.println("Bug");
    		System.exit(0);
    		}
     
    	}
     
    }


  2. #2
    Super Moderator pbrockway2's Avatar
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    Default Re: Reading ints into a multidimensional array

    You could use System.out.println() to make sure you are reading what you expect and assigning that input to whatever you mean to assign it to.

    while(infile.hasNext())
    {
        players[k]=infile.next();
        System.out.println(players[k] + "read and assigned to players[k]");
     
        k++;
     
        if (k==play)
            break;
    }
    for(int j=0; j<par; j++)
    {
        for (int i=0; i<play; i++)
        {
            scores[j][i]=infile.nextInt();
            System.out.println(scores[j][i] + "read and assigned to scores[" + j + "][" + i + "]");
        }
     
    }

  3. #3
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    Default Re: Reading ints into a multidimensional array

    There's a different between the methods '.next()' and '.nextLine()'. "Next" only reads up until a space a line break occurs, next line keeps reading until the file has ended. What you wanna do is something like this:
    Scanner reader = new Scanner(new File(filename));
    while(reader.hasNextLine()){
    String line = reader.nextLine();
    if(!line.equals("")){
    //do whatever with that line
    }
    }

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