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Thread: Initializing

  1. #1
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    Default Initializing

    Here is my code, with the following error that I get, I dunno why its trying to make me initialize a String:

    import java.util.Scanner;

    public class Lab7_Ex2
    {

    public static void main(String [] args)
    {

    Scanner keyboard = new Scanner(System.in);

    int numberCount = 0;
    String numberString;
    int number;
    int total = 0;
    double average = 0.0;

    System.out.print("Enter the first number, or 9999 to exit: ");
    number = Integer.parseInt(numberString);

    while (number !=9999)
    {
    total += number;
    numberCount++;

    System.out.print("Enter a number" + (numberCount + 1) + " or 9999 to exit: ");
    number = Integer.parseInt(numberString);
    }

    if (numberCount > 0)
    {
    average = (double) total / numberCount;
    System.out.print("The average of the numbers is: " + average + ".");
    }

    System.exit(0);
    }
    }
    -------------------------------------------------------------------------------------------------------------------

    ----jGRASP exec: javac -g Lab7_Ex2.java
    Lab7_Ex2.java:21: variable numberString might not have been initialized
    number = Integer.parseInt(numberString);
    ^
    1 error

    ----jGRASP wedge: exit code for process is 1.
    ----jGRASP: operation complete.


  2. #2
    Junior Member Krumpir's Avatar
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    Default Re: Initializing

    Change String numberString; to String numberString = 200;
    Check out my site -> tssolutions.net16.net

  3. #3
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    Default Re: Initializing

    Quote Originally Posted by Krumpir View Post
    Change String numberString; to String numberString = 200;
    If you had thought about it a little more, or if you had taken the trouble to actually test it before posting, you would realize that your suggestion won't compile.

    To the Original Poster: It's OK to declare a String without giving it an initial value, but Java won't let you use it in your program until you have somehow given it a value.

    Didn't you intend to use your keyboard Scanner object to read something into the String before parsing it into an int?


    Cheers!

    Z
    Last edited by Zaphod_b; July 26th, 2012 at 01:05 PM.

  4. #4
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    Default Re: Initializing

    The reason the compiler is complaining is because you never once initialized `numberString`. I suspect you intended to initialize it with something like:
    numberString = keyboard.next();
    ... but unfortunately you never did.
    Besides, given you're utilizing `Scanner`, you are able to skip the `Integer.parseInt()` call and the intermediate `numberString` field completely by calling `Scanner.nextInt()` directly, along with `Scanner.hasNextInt()` to determine whether there is any more input. You can see below for an example of how that would work:

    import java.util.Scanner;
     
    public final class Lab7_Ex2 {
     
      public static void main(String[] argv) {
        final Scanner input = new Scanner(System.in);
     
        int a = 0;
        int n = 1;
     
        System.out.print("Enter the first number, or 9999 to exit: ");
        int i;
        while (input.hasNextInt() && (i = input.nextInt()) != 9999) {
          a += i;
          System.out.print("Enter number " + ++n + ", or 9999 to exit: ");
        }
     
        if (--n > 0) {
          System.out.printf("The average of the numbers is: %#.2f\n", ((double) a) / n); 
        }
      }
    }
    Last edited by veeer; July 29th, 2012 at 03:54 PM. Reason: Adding explanation

  5. #5
    Super Moderator copeg's Avatar
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    Default Re: Initializing

    veeer, please read the following:
    Forum Rules
    The Problem with Spoon-feeding
    Your post above has been edited.

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