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Thread: How to print information from an array

  1. #1
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    Default How to print information from an array

    When I run the application, the memory address prints to the screen. How do I get it to print the information? This is an example of what it is reading from the file.

    Jason White
    265325222
    31
    Computer Science



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

    public class Test
    {
    public static void main(String[] args)
    {
    String lName = null, fName = null, uid = null, major = null;
    int hours = 0, i = 0, ctr = 0;

    Test[] students = null;
    File input = new File("Enrollment.txt");
    Scanner in;

    students = new Test[30];

    try
    {
    in = new Scanner(input);

    while (in.hasNextLine() && i < students.length)
    {
    fName = in.next();
    lName = in.nextLine();
    uid = in.nextLine();
    hours = in.nextInt();
    in.nextLine();
    major = in.nextLine();

    students[i] = new Test();

    System.out.println(students[ctr] = new Test());

    i++;
    }

    ctr++;
    }

    catch (FileNotFoundException e)
    {
    System.out.println("File not found.");
    }
    }
    }


  2. #2
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    Default Re: How to print information from an array

    It may not be causing a problem right now but have you tried using hasNext() instead of hasNextLine() as the latter may return true even if there is nothing in the next line.

    As for your actual question, it prints the memory address because you're trying to handle the array of objects as though it were just a single object. Your problem can be fixed by using System.out.println(Arrays.toString(yourArray)); . If the array contains other arrays, then you would use System.out.println(Arrays.deepToString(yourArray)) ;. In both cases, you must first import java.util.Arrays.

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    Default Re: How to print information from an array

    Another possible problem is the mixing of calls to the methods: next() and nextLine()
    See: Java Scanner not working, difference between next() and nextLine() | Rommel Rico

    Please edit your post and wrap your code with code tags:
    [code=java]
    <YOUR CODE HERE>
    [/code]
    to get highlighting and preserve formatting.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How to print information from an array

    I changed hasNextLine() to hasNext(). System.out.println(Arrays.toString(yourArray)); and System.out.println(Arrays.deepToString(yourArray)) ; didn't seem to work. They both printed the memory address along with a bunch of "null's".

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    Default Re: How to print information from an array

    didn't seem to work.
    They are for debugging to show the complete contents of arrays.
    The Classname@hexaddress is the String returned by a class that does not override the toString() method to return useful data from the class. Add a toString() method that returns a String.
    The nulls are the contents of array slots that have no values assigned.
    If you don't understand my answer, don't ignore it, ask a question.

  6. #6
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    Default Re: How to print information from an array

    that works, thanks

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