I have an array called maze which in, theory, should get modified only in the updateMaze() method. This is because that is the final result I want to output to the console. The problem is when tempMaze gets modified maze is modified as well. This is not supposed to happen. My first thought was that they are pointing to same reference in memory however I checked and that is false. I do have to mention I used clone() at initialization to make their contents similar, and I am not sure if this could be a issue or not. (Even though I think I understand what clone() does I am not familiar enough to know if it is the problem or not.) My code:
public class ThreadTheMaze {
ArrayList<Cell> result = new ArrayList<Cell>();
private String[][] maze;
private String[][] tempMaze;
private int initRowPosition;
private int initColPosition;
private int amtOfRows;
private int amtOfCols;
public ThreadTheMaze(int initRow, int initCol){
initRowPosition = initRow;
initColPosition = initCol;
result.add(new Cell(initRowPosition, initColPosition));
}
public void loadMaze(){
try{
Scanner in = new Scanner(new File("mazeData.txt"));
while (in.hasNextLine()){
amtOfCols = in.nextLine().length();
amtOfRows++;
}
in.close();
maze = new String[amtOfRows][amtOfCols];
in = new Scanner(new File("mazeData.txt"));
for (int r = 0; r < amtOfRows; r++){
String line = in.nextLine();
for (int c = 0; c < amtOfCols; c++){
maze[r][c] = line.substring(0,1);
line = line.substring(1);
}
}
tempMaze = maze.clone();
}catch (FileNotFoundException e){
System.err.print(e);
}
}
public void printMaze(){
for (int r = 0; r < amtOfRows; r++){
for (int c = 0; c < amtOfCols; c++){
System.out.print(maze[r][c]);
}
System.out.println();
}
}
public void updateMaze(){
for (int i = 0; i < result.size(); i++){
maze[result.get(i).getRow()][result.get(i).getColumn()] = "!";
}
}
/**
@return ArrayList of objects 'Cell' that are the solution to the maze. (Note: if no solution then returns empty ArrayList)
*/
public void solve(Cell cell){
tempMaze[cell.getRow()][cell.getColumn()] = "!";
ArrayList<Cell> neighbors = getNeighbors(cell);
if ((cell.getRow() == 0 || cell.getRow() == tempMaze.length-1) || (cell.getColumn() == 0 || cell.getColumn() == tempMaze[0].length-1)){
return;
}
if ((cell.getColumn() == initColPosition && cell.getRow() == initRowPosition) && neighbors.size() < 1){
return;
}
// If not in init position and has no neighbors then backtrack
if ((cell.getColumn() != initColPosition || cell.getRow() != initRowPosition) && neighbors.size() < 1){
result.remove(result.size()-1);
solve(result.get(result.size()-1));
}else if (neighbors.size() >= 1){ // If has neighbors then choose one and call the method again
result.add(neighbors.get(0));
solve(neighbors.get(0));
}
}
/**
@return ArrayList of objects 'Cell' that are empty and available to move to.
*/
private ArrayList<Cell> getNeighbors(Cell cell){
ArrayList<Cell> neighbors = new ArrayList<Cell>();
int row = cell.getRow();
int column = cell.getColumn();
int[][] moveLocs = {{row-1, column}, {row+1, column}, {row, column+1}, {row, column-1}};
for (int r = 0; r < moveLocs.length; r++){
int tRow = moveLocs[r][0];
int tCol = moveLocs[r][1];
if (isValid(tRow, tCol)){
Cell neighbor = new Cell(tRow, tCol);
neighbors.add(neighbor);
}
}
return neighbors;
}
public boolean isValid(int row, int col){
if(row < 0 || row >= amtOfRows){
return false;
}
if (col < 0 || col >= amtOfCols){
return false;
}
if (!tempMaze[row][col].equals(" ")){
return false;
}
return true;
}
}
The class Cell is a simple class with some simple get and set method.
I know this isn't the most concise way to present you my question, but really I can't spot a place were the problem could exist. Thanks.
