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This is from my attempt at the knights tour game, and what I was trying to do here was show the user what moves they could make from whatever position they are in, in the array.

The problem arrives with NextPos[x+1][y-2]!=null in the if statement, as the exception java.lang.ArrayIndexOutOfBoundsException: -2 is thrown.

I know the array is out of bounds at this position, but that was the point, so that it would not print that this position was available.

My question is, is there a way to get the same result* or to catch the exception so it passes?

*To use the out of bounds array in the if().

The array looks like this when printed:

   1  2  3  4
 A{0  0  0  0}
 B{0  0  0  0}
 C{0  0  0  0}

The values for x and y are 0. The Board array is the same size as the NextPos array, but it is an int array.

public static void MoveTo(int x, int y, int Board[][]) {
    TextIO.putln("jhgkgk");
    String NextPos[][] = {
            {"A1", "A2", "A3", "A4"},
            {"B1", "B2", "B3", "B4"},
            {"C1", "C2", "C3", "C4"}
    };


    for (int i = 0; i < 9; i++)
    {
        switch (i) {

            case 1:
                if (NextPos[x + 1][y - 2] != null && Board[x + 1][y - 2] == 0) {
                    TextIO.putln("test to see if the code gets this far :3");
                    TextIO.putln(NextPos[x + 1][y - 2]);
                }
                break;

            case 2:
                if (NextPos[x + 1][y + 2] != null && Board[x + 1][y + 2] == 0) {
                    TextIO.putln(NextPos[x + 1][y + 2]);
                }
                break;

            case 3:
                if (NextPos[x + 2][y - 1] != null && Board[x + 2][y - 1] == 0) {
                    TextIO.putln(NextPos[x + 2][y - 1]);
                }
                break;

            case 4:
                if (NextPos[x + 2][y + 1] != null && Board[x + 2][y + 1] == 0) {
                    TextIO.putln(NextPos[x + 2][y + 1]);
                }
                break;
            case 5:
                if (NextPos[x - 1][y - 2] != null && Board[x - 1][y - 2] == 0) {
                    TextIO.putln(NextPos[x - 1][y + 2]);
                }
                break;

            case 6:
                if (NextPos[x - 1][y + 2] != null && Board[x - 1][y + 2] == 0) {
                    TextIO.putln(NextPos[x + 1][y + 2]);
                }
                break;
            case 7:
                if (NextPos[x - 2][y + 1] != null && Board[x - 2][y + 1] == 0) {
                    TextIO.putln(NextPos[x - 2][y + 1]);
                }
                break;
            case 8:
                if (NextPos[x - 2][y + 1] != null && Board[x - 2][y + 1] == 0) {
                    TextIO.putln(NextPos[x - 2][y + 1]);
                }
                break;
        }

    }
}
false
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butINeedHelpPlease
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    Please format your code properly. Also, please read [this](http://stackoverflow.com/help/how-to-ask) – Turing85 Apr 15 '15 at 20:04
  • Welcome to StackOverflow! The -2 associated with the IndexOutOfBoundsException indicates that you are passing -2 as an array index to NextPos. I'd guess that this occurs when the value of either x is 0, then NextPos[x-2][y+1] would throw this exception, or when y is 0, causing NextPos[x-1][y-2] to throw. Try adding an if statement that checks the values of x and y before you reference the array. – dgvid Apr 15 '15 at 20:11

1 Answers1

0

First of all, you are getting indexOutOfBound, still you want to skip step. You can figure and fix it. AFA your question is concerned, here is a quick fix for you.

Add the check

(y-2>0)

With

NextPos[x+1][y-2]!=null

So change your if condition to

(y-2>0) && NextPos[x+1][y-2]!=null

Iqbal S
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