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Thread: Copying a file to an array and getting exception thrown for input

  1. #1
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    Default Copying a file to an array and getting exception thrown for input

    I am trying to copy the contents of a file into an array.
    The contents of the file is
    John X Doe 4.0 6 8.2 9

    The code the instructor wrote on the board. I inputted it and when trying to run I get the error
    Exception in thread "main" java.lang.NumberFormatException: For input string: "Doe"
    at sun.misc.FloatingDecimal.readJavaFormatString(Floa tingDecimal.java:1224)
    at java.lang.Double.parseDouble(Double.java:510)
    at fileToArray.getInput(fileToArray.java:37)
    at fileToArray.main(fileToArray.java:16)

    I am not sure what happened. Can anyone assist? Thanks

    import java.util.Scanner;
    import java.io.*;
    import java.util.StringTokenizer;
     
    public class fileToArray
    {
      public static void main(String[] args) throws IOException
      {
        String[] names = new String[39]; // array to hold names from a file
        double[][] reals = new double[39][2]; 
        int[][] ints = new int[39][2];
     
        Scanner inFile = new Scanner(new File("Summer13.txt")); // file to get input
        PrintWriter outFile = new PrintWriter("Summer13.out");  // file to write output
     
        int n = getInput(names, reals, ints, inFile);
        int left = leftOver(inFile);
     
      }
       //Methods
         public static int getInput(String[] names, double[][] reals, int[][] ints, Scanner inFile)
         {
          int i = 0,  m;
          String line;
          StringTokenizer st;
     
          //while loop to read file
          while(i < names.length && inFile.hasNext())
          {
             line = inFile.nextLine();
             st = new StringTokenizer(line);
             m = st.countTokens();
             for(int j = 1; j < m-4; j++)
             {
                names[i] = names[i] + " " + st.nextToken();
             }
             reals[i][0] = Double.parseDouble(st.nextToken());
             ints[i][0] = Integer.parseInt(st.nextToken());
             reals[i][1] = Double.parseDouble(st.nextToken());
             ints[i][1] = Integer.parseInt(st.nextToken());
             i ++;
          }
     
              return i;
         }
     
     
     
     
          public static int leftOver(Scanner inFile)
          {
            int left = 0;
            while(inFile.hasNext())
            {
              left++;
              inFile.nextLine();
            }
             return left;
          }
     
    }


  2. #2
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    Default Re: Copying a file to an array and getting exception thrown for input

    Out of respect of Java naming conventions, class names should begin with capital letters.

    Are you required to use StringTokenizer, or can you use String.split()? If you can use split(), I recommend it.

  3. #3
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    Default Re: Copying a file to an array and getting exception thrown for input

    Instructor gave us an assignment to do which was the final for her CS1 class. I did not have this instructor and did not learn StringTokenizer or String.split() in my CS1 class. StringTokenizer was what she wrote when putting this up on the board. I did not notice the typo in my class header. Thanks.

  4. #4
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    Default Reading from a file and storing to array's. Names are working but numbers are not

    I am trying to copy the contents of a file into an array.
    The contents of the file is
    John X Doe 4.0 6 8.2 9

    I had some typos and it would not read the names. Now I got the names storing to an array and when I
    print out the index it shows the John X Doe

    When I am trying to store a number it works with no error but when I try and output the index[0] its not a number but this is shown
    [I@1f934ad

    I am not sure what happened. Can anyone assist? Thanks

    import java.util.Scanner;
    import java.io.*;
    import java.util.StringTokenizer;
     
    public class FileToArray
    {
      public static void main(String[] args) throws IOException
      {
        String[] names = new String[39]; // array to hold names from a file
        double[][] reals = new double[39][2]; 
        int[][] ints = new int[39][2];
     
        Scanner inFile = new Scanner(new File("Summer13.txt")); // file to get input
        PrintWriter outFile = new PrintWriter("Summer13.out");  // file to write output
     
        int n = getInput(names, reals, ints, inFile);
        int left = leftOver(inFile);
     
      }
       //Methods
         public static int getInput(String[] names, double[][] reals, int[][] ints, Scanner inFile)
         {
          int i = 0,  m;
          String line;
          StringTokenizer st;
     
          //while loop to read file
          while(i < names.length && inFile.hasNext())
          {
             line = inFile.nextLine();
             st = new StringTokenizer(line);
             m = st.countTokens();
             names[i] = st.nextToken();
     
             for(int j = 1; j < m-4; j++)
             {
                names[i] = names[i] + " " + st.nextToken();
             }
             reals[i][0] = Double.parseDouble(st.nextToken());
             ints[i][0] = Integer.parseInt(st.nextToken());
             reals[i][1] = Double.parseDouble(st.nextToken());
             ints[i][1] = Integer.parseInt(st.nextToken());
             i ++;
          }
     
              return i;
         }
     
     
     
     
          public static int leftOver(Scanner inFile)
          {
            int left = 0;
            while(inFile.hasNext())
            {
              left++;
              inFile.nextLine();
            }
             return left;
          }
     
    }

  5. #5
    Super Moderator Norm's Avatar
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    Default Re: Reading from a file and storing to array's. Names are working but numbers are not

    when I try and output the index[0] its not a number but this is shown
    [I@1f934ad
    That is what is returned by the toString() method of a single dim int array.
    I don't see a variable named: index in the code. There is a two dim int array named: ints. Is that what you are talking about? ints[0] refers to an int array. ints[0][1] refers to an int
    If you want to print the contents of an array, you can do this:
    System.out.println("an ID "+ java.util.Arrays.toString(theArrayName));
    If you don't understand my answer, don't ignore it, ask a question.

  6. The Following User Says Thank You to Norm For This Useful Post:

    KristopherP (August 31st, 2013)

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    Default Re: Reading from a file and storing to array's. Names are working but numbers are not

    Hello.
    Can you please provide your print statements?
    If you want to print an array using System.out.println(array) then it will not print the elements of array. Instead it will print the hashcode of an object. Because arrays are treated as objects in java.
    So you will need to traverse the entire array and print individual elements by yourself.

    Syed.

  8. #7
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    Default Re: Reading from a file and storing to array's. Names are working but numbers are not

    Sorry that was just meant to imply that I was printing index 0 of the array's. When I went back to check the code I seen that I was trying to print a [] array when they were [][]. I made the change and now it is working. Thanks a lot.

  9. #8
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    Default Re: Copying a file to an array and getting exception thrown for input

    Quote Originally Posted by KristopherP View Post
    I am trying to copy the contents of a file into an array.
    I'm confused over the instructions. An array, as in singular?

    Quote Originally Posted by KristopherP View Post
    The contents of the file is
    John X Doe 4.0 6 8.2 9
    One single line? Or are there more lines? Will each line contain the same exact setup, which appears to be:
    firstName middleInitial lastName double int double int

    Quote Originally Posted by KristopherP View Post
    The code the instructor wrote on the board.
    The instructor give you the code you are supposed to write? Again I do not understand what you mean here.

    Quote Originally Posted by KristopherP View Post
    Exception in thread "main" java.lang.NumberFormatException: For input string: "Doe"
    at sun.misc.FloatingDecimal.readJavaFormatString(Floa tingDecimal.java:1224)
    at java.lang.Double.parseDouble(Double.java:510)
    at fileToArray.getInput(fileToArray.java:37)
    at fileToArray.main(fileToArray.java:16)

    I am not sure what happened. Can anyone assist? Thanks
    The exception means that "Doe" is not a number.
    Add some printlns to see the value of the variables like line, st, m... this will show the symptoms in more detail and help discover the cause

    --- Update ---

    Please do not double post your questions
    Threads merged

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