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Thread: Inserting characters from string into 2d array?

  1. #1
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    Unhappy Inserting characters from string into 2d array?

    Hi there,
    I am new to java and am having trouble with some code... I am trying to input the characters from a string into a 2d array. The array size depends on the amount of characters in the string (get the square root and round up to the nearest int so that the array is a square grid). I'm getting an out of bounds error, but not sure why. I would appreciate any help! Thanks

    This is what I have so far:

    public class Practice {
    	public static void main(String[] args) {
     
    		String text = args[0];
    		text = text.replaceAll("\\s", "");
    		text = text.toLowerCase();
    		System.out.println(text);
     
    		float squareRoot = (float) Math.sqrt(text.length());
    		int dimension = (int) Math.ceil(squareRoot);
    		int x = dimension;
    		int y = dimension;
     
    		 char[] charArray = text.toCharArray();
    		 char[][] myArray = new char[x][y];
    		 int nextChar = 0;
    		 for (int a = 0; a < x; ++a) {
    			 for (int b = 0; b <y; ++b) {
    				 myArray[x][y] = charArray[nextChar]; 
    				 nextChar++;
    			 }
    		 }
    }
    }


  2. #2
    Senior Member PhHein's Avatar
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    Default Re: Inserting characters from string into 2d array?

    You're iterating x*y times, which is likely more than charArray.length, because you round up. So nextchar will be >= than charArray.length, causing the Exception.

  3. The Following User Says Thank You to PhHein For This Useful Post:

    amf19 (April 12th, 2013)

  4. #3
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    Default Re: Inserting characters from string into 2d array?

    ah, thank you.. that makes sense. Still unsure as to how I would go about fixing this though?

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    Senior Member PhHein's Avatar
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    Default Re: Inserting characters from string into 2d array?

    You have to stop looping as soon as nextchar will be >= charArray.length

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    Default Re: Inserting characters from string into 2d array?

    I've tried putting an if statement in, but that doesn't seem to work:

    		char[] charArray = text.toCharArray();
    		char[][] myArray = new char[x][y];
    		int nextChar = 0;
    			for (int a = 0; a < x; ++a) {
    				for (int b = 0; b < y; ++b) {
    					if (nextChar < charArray.length) {
    					myArray[x][y] = charArray[nextChar];
    					nextChar++;
    					}
    			}
    		}

  7. #6
    Senior Member PhHein's Avatar
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    Default Re: Inserting characters from string into 2d array?

    What does "doesn't seem to work" mean? Did you blow up your toaster? What error messages/stack traces do you get now?

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    Default Re: Inserting characters from string into 2d array?

    I still get the same error - out of bounds exception

  9. #8
    Senior Member PhHein's Avatar
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    Default Re: Inserting characters from string into 2d array?

    Aha! You're not using the loop variables as index!
    myArray[a][b] = charArray[nextChar];
    You're using x and y which are out of bounds.

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    amf19 (April 12th, 2013)

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    Default Re: Inserting characters from string into 2d array?

    You're right! Still out of bounds error though after fixing!!

    --- Update ---

    Wait ignore last post, it worked! Thank you so much

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