Thread: Binary algorithm assignment.

Hello Community,

I'm working on an assignment for my data structure & algorithm class. My whole summer of not programming in java made me a extremely rusty. I need help creating an array of objects via a class I created. Never mind what I comment out I will work on that later. Here is my code below.

/**
 * 
 *  
 *  CSC 385 
 *  Module 5
 *  
 */
 
 
import java.util.*;
 
public class Module5
{
 
   public static void main(String[] args)
   {
 
     Scanner scan = new Scanner(System.in);      
     Comparable test = new Comparable(10);  
 
 
     for(int i=0 ; i < 10; i++)
     {
        // test[i] = new Comparable();
         System.out.print(" Input value:" + i + " " );
         //test[i] = scan.nextInt();
 
     }
 
 
   }
 
 
  /** public int binarySearch(Comparable[] objArray, Comparable searchObj)
   {
 
      int low = 0;
      int high = objArray.length - 1;
      int mid = 0;  
      int temp = 0;
 
 
      while (low <= high){
 
       mid = (low + high) / 2;
 
       if (arrayIndex.compareTo(searchObj) < 0)
       {
        low = mid + 1;
        temp = low;
       }
       else if (objArray[mid].compareTo(searchObj) > 0)
       {   
        high = mid - 1;
        temp = high;
       }
       else
       {
         return mid;
       }
 
   }
     return temp; 
 
      if( temp < 0)
      {
       temp+=1;
      }
 
 
   } */
 
 
 
 
}

 
public class Comparable
{
 
    Object[] objArray; 
 
 
    public Comparable( Object objArray, int x)  
     {
 
        objArray = this.objArray;
        objArray = new Comparable[x];
 
    }
 
    public Comparable(Object[] o)
    {
        objArray = o;
 
    }
 
    public Comparable(int x)
    {
        //objArray = this.objArray;
        objArray = new Comparable[x];
 
    }
 
    public void setArray(int x){
        objArray = new Comparable[x];
    }
 
}

For some reason when I try to create an object from my class and start to add int values to that array object I receive this error message.

********************************
Array required, but Comparable found

You are using syntax here that suggestions that you are trying access to as array element. The variable you trying is not an array, though.
********************************

It seems my syntax is wrong of creating this array object. I have the right idea of want to store objects in the array, but I don't know what I'm doing wrong. Any suggestions as well as documentation I can review?

Much Appreciated!
Rain_Maker

errormessage.JPG


I'm using BlueJ as my IDE. So I hope this error message is able for you to answer my question.

seconderrormessage.JPG

Originally Posted by Norm

Please copy the text and paste it here, no images. Text for responses can't be copied from images.

Be sure to rename your class.

Norm,

BlueJ will not allow me to copy the error message as text. I can only write out the error message or provide a screen shot. Is there anyway else to help. FYI I was able to rename my class FYI.

Let me try that....one moment please

--- Update ---

I just rqn my code via the command prompt.(Learned something new )


C:\Users\......>javac Module5
error: Class names, 'Module5', are only accepted if annotation processing is ex
licitly requested
1 error


Weird error message. I don't know what this mean?

Microsoft Windows [Version 6.0.6001]
Copyright (c) 2006 Microsoft Corporation. All rights reserved.

C:\Users\.....>cd Documents

C:\Users\......\Documents>dir
Volume in drive C has no label.
Volume Serial Number is 367B-6966

Directory of C:\Users\......\Documents

09/27/2014 07:15 PM <DIR> .
09/27/2014 07:15 PM <DIR> ..
04/25/2014 06:00 AM 10,521 1.docx
09/04/2014 08:39 PM <DIR> Cisco Fall Semster
09/01/2014 03:13 PM 139,798 CompTIA_A_220-801_Objectives.pdf
09/01/2014 03:13 PM 140,209 CompTIA_A_220-802_Objectives.pdf
09/02/2014 07:48 PM 7,852 Counter (1).html
09/02/2014 07:47 PM 2,574 Counter (1).java
09/02/2014 06:59 PM 7,852 Counter.html
09/02/2014 06:59 PM 2,574 Counter.java
09/02/2014 07:47 PM 315 CounterInitializationException (1).java
09/02/2014 06:59 PM 315 CounterInitializationException.java
09/02/2014 07:47 PM 10,847 CounterTest (1).java
09/02/2014 06:59 PM 10,847 CounterTest.java
09/24/2014 01:46 PM <DIR> Data Structure & Alogrithms
06/23/2014 07:57 PM 22,081
09/08/2014 08:57 PM 22,522
09/09/2014 12:34 PM 20,332
03/05/2014 11:34 PM <DIR> LoopingTesting
09/14/2014 09:42 PM <DIR> Module2
09/20/2014 06:06 PM <DIR> Module3
09/20/2014 07:49 PM <DIR> Module4
09/28/2014 09:46 AM <DIR> Module4hwk
09/28/2014 10:16 PM <DIR> Module5
09/02/2014 07:47 PM 508,603 Module_2 _hw (1).pdf
09/02/2014 06:59 PM 508,603 Module_2 _hw.pdf
03/31/2014 11:25 PM <DIR> New Unity Project
07/02/2014 09:34 PM <DIR> PracticeTest
04/21/2014 08:14 PM <DIR> Quiz 2 Prepartion
09/20/2014 06:05 PM 6,646 RecursionDemo.zip
06/23/2014 02:19 PM 12,174 signature.docx
07/02/2014 07:59 PM <DIR> testClass
05/04/2014 10:43 PM 16,001 The Speakers Engage Series for my Engaged
Citizenship Common Experience requirement has been an engaging and intriguing e
xperienc1.docx
19 File(s) 1,450,666 bytes
14 Dir(s) 50,228,674,560 bytes free

C:\Users\.......\Documents>javac Module5
error: Class names, 'Module5', are only accepted if annotation processing is exp
licitly requested
1 error

C:\Users\......\Documents>javac Module5.java
javac: file not found: Module5.java
Usage: javac <options> <source files>
use -help for a list of possible options

C:\Users\....\Documents>

I'm receiving this error message now. I do have my java files in a package. Could that be the problem on why I have this error message now?

Originally Posted by Norm

Where is the source file: Module5.java? The javac program could not find it.

It located here....Don't know what else to really do..Should I move it?javaFile.JPG

Norm,

I was able to find my error in my syntax but I have another problem. I'm trying to use the compareTo method. I'm comparing an integer and another integer from an object array. If I try to compile my code I receive this error message:Cannot find Symbol method retrieveArray()

 
/**
 * 
 *  Gregory B Shavers Jr
 *  CSC 385 
 *  Module 5
 *  
 */
 
 
import java.util.*;
 
public class Module5
{
 
   public static void main(String[] args)
   {
 
     SearchIndex test = new SearchIndex();  
     test.addArray(1,0); 
     test.addArray(2,1); 
     test.addArray(3,2); 
     test.addArray(4,3); 
     test.addArray(5,4); 
     test.addArray(6,5);
     test.addArray(7,6); 
     test.addArray(8,7); 
     test.addArray(9,8); 
     test.addArray(10,9);       
 
   }
 
 
   public int binarySearch(Object[] objArray, int searchObj)
   {
 
      int low = 0;
      int high = objArray.length - 1;
      int mid = 0;  
      int temp = 0;
 
 
      while (low <= high){
 
       mid = (low + high) / 2;
 
       int i = objArray[mid].rretrieveArray();   
 
       if (mid.compareTo(searchObj) < 0)
       {
        low = mid + 1;
        temp = low;
       }
       else if (objArray[mid].compareTo(searchObj) > 0)
       {   
        high = mid - 1;
        temp = high;
       }
       else
       {
         return mid;
       }
 
   }
   return temp; 
 
      if( temp < 0)
      {
       temp++;
      }
 
 
   }
 
 
 
 
}

 
 
 public class SearchIndex
{
 
    Object[] objArray; 
 
    public SearchIndex(){
    }
 
    public SearchIndex( Object objArray, int x)  
    {
 
        objArray = this.objArray;
        objArray = new SearchIndex[x];
 
    }
 
    public SearchIndex(Object[] o)
    {
        objArray = o;
 
    }
 
    public SearchIndex(int x)
    {
        //objArray = this.objArray;
        objArray = new Comparable[x];
 
    }
 
    public void addArray(Object a , int i)
    {
            objArray[i] = a;        
    }
 
    public Object[] retrieveArray()
    {
            return objArray;        
    }
}

Originally Posted by Norm

That array is defined as holding Object items. The Object class does not have that method.

Could you elaborate on that? If I created my array objects shouldn't my data be recoverable from my objects? I'm not quite sure what I need to code.

Why are you using Object class objects instead of the class that has the retrieveArray() method?[/QUOTE]

My teachers wants us to use object Arrays for this assignment and compare them to a int value to see if its in the array object list or not.