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POMaze generation - ArrayIndexOutOfBoundsException
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copied!<p>I tried generate maze with two entries at the opposite sides.</p> <p>But when I trying to run this test program I catch <code>ArrayIndexOutOfBoundsException</code>:</p> <pre><code>Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at maze.variation.MyMaze.generateMaze(MyMaze.java:61) at maze.variation.MyMaze.generateMaze(MyMaze.java:63) at maze.variation.MyMaze.generateMaze(MyMaze.java:51) at maze.variation.MyMaze.generateMaze(MyMaze.java:51) at maze.variation.MyMaze.generateMaze(MyMaze.java:51) at maze.variation.MyMaze.generateMaze(MyMaze.java:51) at maze.variation.MyMaze.generateMaze(MyMaze.java:35) at maze.variation.MyMaze.<init>(MyMaze.java:14) at maze.variation.MyMaze.main(MyMaze.java:137) </code></pre> <p>I can't figure out what's wrong. It's some easy failures, but I can't find weak place.</p> <p><strong>Code:</strong></p> <pre><code>public class MyMaze { private int dimension; // dimension of maze private char[][] grid; private boolean[][] marked; private boolean[][] visited; private boolean done = false; public MyMaze(int aDimension) { dimension = aDimension; grid = new char[dimension][dimension]; init(); generateMaze(); } private void init() { // initialize border cells as already visited visited = new boolean[dimension + 2][dimension + 2]; for (int x = 0; x < dimension + 2; x++) visited[x][0] = visited[x][dimension + 1] = true; for (int y = 0; y < dimension + 2; y++) visited[0][y] = visited[dimension + 1][y] = true; // initialze all walls as present visited = new boolean[dimension + 2][dimension + 2]; marked = new boolean[dimension + 2][dimension + 2]; for (int x = 0; x < dimension + 2; x++) for (int y = 0; y < dimension + 2; y++) marked[x][y] = true; } // generate the maze starting from lower left private void generateMaze() { generateMaze(1, 1); } // generate the maze private void generateMaze(int x, int y) { visited[x][y] = true; // while there is an unvisited neighbor while (!visited[x][y + 1] || !visited[x + 1][y] || !visited[x][y - 1] || !visited[x - 1][y]) { // pick random neighbor while (true) { double r = Math.random(); if (r < 0.25 && !visited[x][y + 1]) { marked[x][y] = marked[x][y + 1] = false; generateMaze(x, y + 1); // 51 line break; } else if (r >= 0.25 && r < 0.50 && !visited[x + 1][y]) { marked[x][y] = marked[x + 1][y] = false; generateMaze(x + 1, y); break; } else if (r >= 0.5 && r < 0.75 && !visited[x][y - 1]) { marked[x][y] = marked[x][y - 1] = false; generateMaze(x, y - 1); break; } else if (r >= 0.75 && r < 1.00 && !visited[x - 1][y]) { // 61 line marked[x][y] = marked[x - 1][y] = false; generateMaze(x - 1, y); break; } } } } // solve the maze starting from the start state public void solve() { for (int x = 1; x <= dimension; x++) for (int y = 1; y <= dimension; y++) visited[x][y] = false; done = false; solve(1, 1); } // draw the maze public void draw() { for (int x = 1; x <= dimension; x++) { for (int y = 1; y <= dimension; y++) { if (marked[x][y]) { grid[x][y] = '*'; } } } System.out.print(this.grid); } /** * Overridden method to generate a human readable maze state. */ @Override public String toString() { StringBuffer sb = new StringBuffer(1024); for (int x = 0; x < this.dimension; x++) { for (int y = 0; y < this.dimension; y++) { sb.append(this.grid[x][y]); } sb.append("\n"); } return sb.toString(); } public static void main(String[] args) { int userDimension = 40; MyMaze maze = new MyMaze(userDimension); maze.draw(); } } </code></pre> <p>I don't know how to find solution for creating two entries at opposite sides (north and south) and they need to have connection to maze. Any suggestions?</p> <ul> <li><em><strong>How to solve this error trouble?</em></strong></li> </ul> <p><strong>Edit:</strong></p> <p>I added this check into while loop:</p> <pre><code> // pick random neighbor while (true) { if (x == 0 || x == 1 || y == 0 || y == 1) continue; // method's rest </code></pre> <p>It looks ok now.If you running this code you'll find no output. But it should be.<br> <strong><em>Why this doesn't print maze correctly?</em></strong></p>

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