Favouring two dimensional array

Sd1/P/life/V3/src/main/java/LifeWorld.java

@@ -13,8 +13,8 @@ public class LifeWorld extends World {
 
    private static int  initialLivingPercentage = 25;
 
-   private static final int 
-     width = 50,
+   static private final int 
+     width = 80,
      height = 50;
    
    public static final int cellSize = 10; // Minimum of 3 pixel in width here yields a (cellSize-2)x(cellSize-2) pixel visible cell
@@ -34,7 +34,7 @@ public class LifeWorld extends World {
     }
 
    private final GreenfootImage gridImage;
-   private final Cell[] cells;
+   private final Cell[][] cells;
 
    /**
     * The probability for a newly born cell
@@ -56,13 +56,13 @@ public class LifeWorld extends World {
       super(width, height, cellSize);
       gridImage = getBackground();
       drawGrid();
-      cells = createCells();  // Create an initialize array all cells.
+      cells = new Cell[width][height];  // Create cells array container.
+      createCells();
 
-      // Having created all cells we may now determine each cell's neighbors.
+      // Having created all cells we may now determine and set each cell's set of neighbors.
       for (int x = 0; x < width; x++) {  
          for (int y = 0; y < height; y++) {
-            final Cell centerCell = cells[getCellIndex(x, y)];
-            centerCell.setNeighbors(getCellsNeighbours(x, y));
+            cells[x][y].setNeighbors(getCellNeighbours(x, y));
          }
       }   
    }
@@ -73,8 +73,10 @@ public class LifeWorld extends World {
     * calling any actor's {@link Actor#act()} methods methods.
     */
    public void act() {
-      for (final Cell c : cells) {
-         c.saveCurrentToPreviousState();
+      for (int x = 0; x < width; x++) {
+         for (int y = 0; y < height; y++) {
+            cells[x][y].saveCurrentToPreviousState();
+         }
       }
    }
 
@@ -108,41 +110,21 @@ public class LifeWorld extends World {
       // (height-1) __________..._____
    }
 
-   /**
-    * Turn (x|y) coordinates into linear cell array index 
-    * values ranging from 0 to (width * height - 1).
-    * 
-    * Consider a simplified example of an array having width = 4 and
-    * height = 3:
-    * 
-    *   {(0|0) (1|0) (2|0) (3|0)} --> Linear array Index values {0, 1, 2, 3}
-    *   {(0|1) (1|1) (2|1) (4|1)} --> Linear array Index values {4, 5, 6, 7}
-    *   {(0|2) (1|2) (2|2) (4|2)} --> Linear array Index values {8, 9, 10, 11}
-    * 
-    * @param x horizontal position in cell coordinates
-    * @param y vertical position in cell coordinates
-    * @return The linear array index.
-    */
-   private int getCellIndex(int x, int y) {
-      return x + y * width;
-   }
-
    /** Create the array of cells and randomly turn some of them on
     *  according to {@link #setInitialLivingPercentage(int)}.
     */
-   private Cell[] createCells() {
-      final Cell [] cellsToReturn =              // Variable name has to be different from LifeWorld.cells
-            new Cell[width * height];              // in order to initialize final variable.
+   private void createCells() {
       for (int x = 0; x < width; x++) {
          for (int y = 0; y < height; y++) {
             final Cell c = new Cell(cellSize,      // Create a cell having a fixed probability
-                  getRandomLifeOrDeadState());       // to be either dead or alive.
-            cellsToReturn[getCellIndex(x, y)] = c; // A separate array allows for easier access than via
+                  getRandomLifeOrDeadState());     // to be either dead or alive.
+            
+            cells[x][y] = c;                       // A separate array allows for easier access than via
+            
             // Greenfoot's own "world" object accounting mechanism.
-            addObject(c, x, y);                    // Add to Greenfoot world.
+            addObject(c, x, y);                    // Add to Greenfoot world as well.
          }
       }
-      return cellsToReturn;                      // Will be assigned to variable cells
    }
 
    /**
@@ -163,7 +145,7 @@ public class LifeWorld extends World {
     * @param y The given cell's y-position
     * @return The array of all neighboring cells.
     */
-   private Cell[] getCellsNeighbours(final int x, final int y) {
+   private Cell[] getCellNeighbours(final int x, final int y) {
       // Rectangular limits corresponding to the 9 different boundary
       // related situations being described in the above Javadoc.
       //
@@ -179,7 +161,7 @@ public class LifeWorld extends World {
       for (int dx = xMin; dx <= xMax; dx++) {
          for (int dy = yMin; dy <= yMax; dy++) {
             if (dx != x || dy != y) {// Exclude center cell
-               neighbors[neighborIndexCount++] = cells[getCellIndex(dx, dy)];
+               neighbors[neighborIndexCount++] = cells[dx][dy];
             }
          }
       }