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Thread: logic error somewhere.. working with try & catch, simple array.. please help

  1. #1
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    Default logic error somewhere.. working with try & catch, simple array.. please help

    // CS 0401 Fall 2010
    // Lab 10
    // You must modify this file so that it works as described in the lab handout.
    import java.util.*;
    import java.io.*;
    import java.lang.*;
     
    public class lab10
    {
    	public static void main(String [] args) throws IOException
    	{
    		Scanner inScan, fScan = null;
    		int [] A = new int[5];
    		inScan = new Scanner(System.in);
    		String fName;
     
     
    		do
    		{
    			System.out.println("Please enter the file to read from: ");
    			fName = inScan.nextLine();
    		} while (!fName.toString().equals("lab10out.txt"));
     
     
    		fScan = new Scanner(new File(fName));
    		String nextItem = " ";
    		int nextInt = 0;
    		int i = 0;
     
    		while (fScan.hasNextLine())
    		{
    			try
    			{
    				nextItem = fScan.nextLine(); // reads all lines as strings
    				nextInt = Integer.parseInt(nextItem); // then reads all lines as ints
    				A[i] = nextInt;     // all of the numbers are stored in 
    				i++;                 // processes through array until final line is reached
     
    			if (i>A.length)    // if incremented more than array size 
    			{
    				int [] temp = new int[A.length*2];  // create new array with the size of array A * 2 ( doubled) == A = 10
    				int j;
    				for(j=0; j<A.length; j++)
    				{
    					temp[j] = A[j];  // put all of the values of old array into new array Temp 
    				}
    				temp[j] = nextInt;  // all the new numbers are stored in nextInt soo nextInt = 10
    				i++;
    				A = new int[temp.length]; // new Array size now array size A is 10
     
     
    			}
    			}catch (NumberFormatException e1)
    			{
    				System.out.println(nextItem + "  is not an integer -- Ignored");
    			}catch (ArrayIndexOutOfBoundsException e2)
    			{
    				System.out.println("Resizing array from " + A.length + "to" +
    								(A.length*2) + ".");
     
    			}
    		}
     
    		System.out.println("Here are your " + i + " items:");
    		for (int j = 0; j < i; j++)
    		{
    			System.out.println(A[j] + " ");
    		}
    	}
    }

    Heres my output:
    bogus is not an integer -- Ignored
    weasel is not an integer -- Ignored
    Resizing array from 5to10.
    Resizing array from 5to10.
    3.5 is not an integer -- Ignored
    Resizing array from 5to10.
    Resizing array from 5to10.
    Resizing array from 5to10.
    Resizing array from 5to10.
    Resizing array from 5to10.
    Resizing array from 5to10.
    Here are your 5 items:
    100
    200
    300
    150
    400




    Needed output
    bogus is not an integer -- ignored
    weasel is not an integer -- ignored
    Resizing array from 5 to 10
    3.5 is not an integer -- ignored
    Resizing array from 10 to 20
    Here are your 13 items:
    100
    200
    300
    150
    400
    600
    250
    800
    50
    500
    450
    600
    550


  2. #2
    Crazy Cat Lady KevinWorkman's Avatar
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    Default Re: logic error somewhere.. working with try & catch, simple array.. please help

    I suggest you step through your code with a debugger.

  3. #3
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    Default Re: logic error somewhere.. working with try & catch, simple array.. please help

    Have you tried putting your if(i>a.length) block inside of your catch block ? It looks to me like you are going to keep throwing the exception until you change your code to check A[i] is within bounds before attempting to assign it.

    good luck!

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