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Thread: Java Program with text file - Help!

  1. #1
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    Default Java Program with text file - Help!

    I've been given a coding problem that I'm having trouble with. I've been given the code below along with a text file. The text file contains the folowing:

    Chen Ruolin 9.2 9.3 9 9.9 9.5 9.5 9.6 9.8
    Emilie Heymans 9.2 9.2 9 9.9 9.5 9.5 9.7 9.6
    Wang Xin 9.2 9.2 9.1 9.9 9.5 9.6 9.4 9.8
    Paola Espinosa 9.2 9.3 9.2 9 9.5 9.3 9.6 9.8
    Tatiana Ortiz 9.2 9.3 9 9.4 9.1 9.5 9.6 9.8
    Melissa Wu 9.2 9.3 9.3 9.7 9.2 9.2 9.6 9.8
    Marie-Eve Marleau 9.2 9.2 9.2 9.9 9.5 9.2 9.3 9.8
    Tonia Couch 9.2 9 9.1 9.5 9.2 9.3 9.4 9.6
    Laura Wilkinson 9.7 9.1 9.3 9.4 9.5 9.4 9.6 9.2


    import java.io.*;
    import java.util.*;
     
    public class readFile {
     static Scanner infile = null;
     
     public static void main(String[] args) throws IOException {
     
      infile  = new Scanner(new FileReader("diving_data.txt"));
     
            String str = null;
            double score = 0.0;
            //I know there are 9 lines of data
            for(int l=0; l<9; l++) {
       //System.out.println("The data from line " + l);
       str = infile.next();
       System.out.print(str + " ");
       str = infile.next();
       System.out.print(str + " ");
       //I know there are 8 scores per diver
       for(int s=0; s<8; s++) {
        score = infile.nextDouble();
           System.out.print(score + " ");
       }
       System.out.println();
      }
     
     }
     
    }

    I've been given the following instructions along with this... to be honest I'm not even really sure as to what is being asked of me:

    Per the following UML diagram you are to write a Diver class. Then using the attached data file I want another program that reads the data processing one line at a time to instantiate your Diver class, populate the Diver's data attributes, and then outputting that Diver's information by calling it's toString method.

    In a diving competition, each contestant's score is calculated by dropping the lowest and highest scores and then adding the remaining scores. Write a program that reads the provided data file formatted as depicted in the following table. For each diver output the diver's name and total score using the above scoring rules. Format each diver's total score to two decimal places. So for example, the output for Chen Ruolin below would be: Chen Ruolin 56.90 points.

    I'm just wondering what exactly I should be doing for this code, and how I should go about completing it. I've never been this lost on any of the programs I've dont before. Help is greatly appreciated.


  2. #2
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    Default Re: Java Program with text file - Help!

    Just a quick comment on the code because I don't have a lot of time ... use split(" ") to split the String into an array, deliminated by a space " " character.

    str = infile.nextLine();
    String[] record = str.split(" ");
     
    // Now each field in the line can be accessed as an array
    String firstName = record[0];
    String lastName = record[1];
    double score1 = Double.parse(record[2]);
    //etc...

  3. #3
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    Default Re: Java Program with text file - Help!

    Ahhh so I need to use an array to split up the data in the txt file. Is there a specific spot in the code where the array needs to go?

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    Default Re: Java Program with text file - Help!

    Use the split() method after a line has been read from the file and before the code needs to access the data in the line. The split() method creates the array and fills it the the tokens that were on the line. To see what is in the array, use the Arrays class's toString() method:
    System.out.println("an ID "+ java.util.Arrays.toString(theArrayName));
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Java Program with text file - Help!

    import java.io.*;
    import java.util.*;
     
    public class readFile {
     static Scanner infile = null;
     
     public static void main(String[] args) throws IOException {
     
      infile  = new Scanner(new FileReader("diving_data.txt"));
     
            String str = null;
            double score = 0.0;
     
             str = infile.nextLine();
    String[] record = str.split(" ");
     
    // Now each field in the line can be accessed as an array
    String firstName = record[0];
    String lastName = record[1];
    double score1 = Double.parseDouble(record[2]);
     
            //I know there are 9 lines of data
            for(int l=0; l<9; l++) {
       //System.out.println("The data from line " + l);
       str = infile.next();
       System.out.print(str + " ");
       str = infile.next();
       System.out.print(str + " ");
       //I know there are 8 scores per diver
       for(int s=0; s<8; s++) {
        score = infile.nextDouble();
           System.out.print(score + " ");
       }
       System.out.println();
      }
     
     }
     
    }

    I've attempted to implement the code into my code to test it out, but I'm getting some crazy errors. I'm very lost as to what the issue is.

    Output:

    java.lang.NumberFormatException: For input string: "9.2 9.3 9 9.9 9.5 9.5 9.6 9.8"
    at sun.misc.FloatingDecimal.readJavaFormatString(Unkn own Source)
    at java.lang.Double.parseDouble(Unknown Source)
    at readFile.main(readFile.java:20)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at edu.rice.cs.drjava.model.compiler.JavacCompiler.ru nCommand(JavacCompiler.java:272)
    >

  6. #6
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    Default Re: Java Program with text file - Help!

    java.lang.NumberFormatException: For input string: "9.2 9.3 9 9.9 9.5 9.5 9.6 9.8"
    at java.lang.Double.parseDouble(Unknown Source)
    at readFile.main(readFile.java:20)
    That String can not be converted to a double. It needs to be split into separate tokens like: "9.2" and "9.3" which can be converted to double values.

    What character is between the numbers in that String?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Java Program with text file - Help!

    It is a space in between each number.

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    Default Re: Java Program with text file - Help!

    Are you sure? Do you have a hex editor that you can look at the file with to see what is in it?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Java Program with text file - Help!

    If I open the file with a text editor it seems to be a space in between each number. If it was not a space would i just have to change the split(" ") to whatever the character is?

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    Default Re: Java Program with text file - Help!

    Look at the file in a hex editor to see what is between the numbers.

    have to change the split(" ") to whatever the character is?
    Yes.
    If you don't understand my answer, don't ignore it, ask a question.

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