loading an integer data file into an integer array

[Bill Stanard]

In preparation for a computing contest here in So. Florida, I'm trying to figure out a simple method to read a numerical data file into an array so that I can then massage the numbers in various ways. This has turned into a daunting task because of unicode issues. The data file looks like this

5
1224345153
2
1112
3
311222
0

where 0 signals an end of file. I can get the file contents to print out just peachy (in the standard output, bottom output box, using JGrasp), but I cannot find a simple way to load this data file AS INTEGERS into an integer array.
I load the array as follows:

 
               while((c = istream.read()) != -1)
               {
                  arrayY[i] = c; 
                  i++; //increments i
               }    

What loads is as follows:

 53 13 10 49 50 50 52 51 52 53 49 53 51 13 10 50 13 10 49 49 49 50...
    

This has been printed out with the following:

               for (int b = 0; b < size; b++)
               {
                  System.out.print(" " + arrayY[b]);
               }    

I understand that what is being loaded is unicode for 5 [53] followed by the equivalent of a new-line [13 10] followed by unicode for the next 10 integers, et cetera. What I would like to do is to populate the integer array with the integers from the data file.

Any suggestions?

[Keith Lynn]

I would do something like this.

The numbers are stored in a file called numbers.txt.

5
123423
2424
25
365
235
0

import java.io.*;
import java.util.*;
 
public class ReadNumbers {
 
   public static void main(String[] args) {
      try {
         FileReader file = new FileReader("numbers.txt");
         BufferedReader input = new BufferedReader(file);
 
         List<Integer> list = new ArrayList<Integer>();
 
         String temp = "";
 
         while ((temp = input.readLine()) != null)
            if (!temp.trim().equals("0"))
               list.add(new Integer(temp));
 
         input.close();
 
         for (Integer number : list)
            System.out.print(number + " ");
      } catch (IOException ie) {
         System.out.println(ie);
      }
   }
 
}

The output is

5 123423 2424 25 365 235

[fred rosenberger]

i think what you want to do is read the file a line at a time, as a string. then use the Integer.valueOf() method to convert it to an Integer.

then you can either store that, or convert it to an int and store it.

[Bill Stanard]

Thanks, Keith... Looks good and compiles, but I get an error when I run it

  
Exception in thread "main" java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.<init>(Unknown Source)
at ReadNumbers.main(ReadNumbers.java:19)

Any suggestions?

[Ernest Friedman-Hill]

Indeed, a blank line is not a number. So you need to test for that so you can skip the blank lines that apparently appear in the file. Before calling Integer.valueOf, you need to check if the String is "".