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Thread: Outofbounds error

  1. #1
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    Default [SOlved]Outofbounds error

    //Lab 3 Library By Parth Patel
    import java.util.Random;
    import java.util.*;
    import java.io.*;
    import java.util.logging.*;
    public class ParthLibraryLab3{
          int[]array;
          public void userinput(){
              Scanner patel = new Scanner(System.in);
              System.out.println("Please Enter the length of the Random Array: ");
              int size = patel.nextInt();
          }
     
     
     
     
        public void getArrayOfRandomNumbers(int size){
            Random random1 = new Random(System.currentTimeMillis());
            array = new int[size];
            for (int i = 0; i < size; i++){
            array[i] = random1.nextInt(1500);
            //
            }
     
     
           }
          public void displayArrayToScreen(){
                System.out.println("The array contents are: ");
                for(int i = 0; i < array.length; ++i)
     
                System.out.print(array[i]);
     
        }
          public void writeArrayToFile(){
              PrintWriter output = null;
              try{
                  System.out.println("Enter the name of the files to create: ");
                  Scanner PSP = new Scanner (System.in);
                  File file = new File(PSP.nextLine());
                  output = new PrintWriter(file);
                  for(int i = 0; i < array.length; ++i){
                      output.print(array[i] + ",");
                  }
     
              }catch(IOException ex){
                  Logger.getLogger(ParthLibraryLab3.class.getName()).log(Level.SEVERE, null, ex);
     
              }finally{
                  output.close();
              }
     
          }
        public void selectionSort(int[] array, int startingIndex){
            if(startingIndex >= array.length +1){
                return;
            }
            int minimumIndex = startingIndex;
            for(int index = startingIndex -1; index < array.length; index++){
                if(array[index] < array[minimumIndex]){
                    minimumIndex = index;
                }
                startingIndex = indexOfSmallest();
            }
            int temporary = array[startingIndex];
            array[startingIndex] = array[minimumIndex];
            array[minimumIndex] = temporary;
            selectionSort(array,startingIndex +
                    +1);
        }
            public void SelectionSort(){
              int LargestNumber = 0;
              int SmallestNumber = 0;
              int IndexNumber = 0;
              for(int i = 1; i < array.length; ++i)
                  if(array[i] > array[i-1]){
                      LargestNumber = array[i];
                      IndexNumber = i;
                  }
              SmallestNumber = indexOfSmallest();
          }
     
          public int indexOfSmallest(){
              int result = 2000;
              for(int i = 1;i < array.length; ++i)
                  if(array[i] < array[i-1])
                      result = i;
              return result;
          }
     
          }
    Main
    //Lab 3 By Parth Patel Main
     
    public class ClientParth {
        public static void main(String[] patel){
     
     
      ParthLibraryLab3 Snowflake = new ParthLibraryLab3();
     
      Snowflake.userinput();
      Snowflake.getArrayOfRandomNumbers(3);
      Snowflake.writeArrayToFile();
      Snowflake.displayArrayToScreen();
      Snowflake.indexOfSmallest();
      Snowflake.SelectionSort();
      Snowflake.selectionSort(Snowflake.array, 0);
     
     
     
     
     
     
     
     
     
        }
     
     
    }
    the error

    run:
    Please Enter the length of the Random Array:
    4
    Enter the name of the files to create:
    5
    The array contents are:
    Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
    at ParthLibraryLab3.selectionSort(ParthLibraryLab3.ja va:59)
    at ClientParth.main(ClientParth.java:15)
    28884980Java Result: 1
    BUILD SUCCESSFUL (total time: 4 seconds)

    Help me, please!
    Last edited by tendulkarfan4life; February 14th, 2011 at 05:56 PM.


  2. #2
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    Default Re: Outofbounds error

    First,

    In main function you call Snowflake.selectionSort(Snowflake.array, 0). If startingIntex has zero value, then index starts with -1 and the array[-1] is called.

     
    for (int index = startingIndex - 1; index < array.length; index++) {
     
    				if (array[index] < array[minimumIndex]) {
    					minimumIndex = index;
     
    				}
    				startingIndex = indexOfSmallest();
    			}

    Second,

    is that correct?

     
    if(startingIndex >= array.length + 1){
    				return;
    			}

    I would think so:

     
    if(startingIndex >= array.length){
    				return;
    			}

    because the last index of array is (size - 1)

    helped?

  3. #3
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    Default Re: Outofbounds error

    And my main looks like this:
    public class ClientParth {
    public static void main(String[] patel){


    ParthLibraryLab3 Snowflake = new ParthLibraryLab3();

    Snowflake.userinput();
    Snowflake.getArrayOfRandomNumbers(3);
    Snowflake.writeArrayToFile();
    Snowflake.displayArrayToScreen();
    Snowflake.indexOfSmallest();
    Snowflake.SelectionSort();
    Snowflake.selectionSort(Snowflake.array, -1);

    Hmmm i get this out put with the following mistakes corrected.

    run:
    Please Enter the length of the Random Array:
    5
    Enter the name of the files to create:
    parth
    Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -2
    The array contents are:
    at ParthLibraryLab3.selectionSort(ParthLibraryLab3.ja va:59)
    at ClientParth.main(ClientParth.java:15)
    8781252382Java Result: 1

  4. #4
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    Default Re: Outofbounds error

    Your code above says you're still starting at less than 0.

    You can't do that.


    if(startingIndex >= array.length +1){
    return;

    If that is turned to

    if (startingIndex >= array.length || startingIndex < 0)
    {
    return;

    Your problem should go away...though if the problem is not from that directly...it'll return and not sort (as you told it to.)

    Ahhhh...got it I think

    for(int index = startingIndex -1; index < array.length; index++){

    You shouldn't start at less than 0.

    However, index should never be less than 0, which it will be even if starting index is 0. It'll say IndexOutOfBounds -1.

    As you're starting with -1, it's saying IndexOutOfBounds -2.

    Try changing that to

    for (int index = startingIndex(perhaps); index < array.length; index++)
    Last edited by javapenguin; February 13th, 2011 at 11:59 PM. Reason: Found the problem! :)

  5. #5
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    Default Re: Outofbounds error

    thanks you, it worked!