Question

im attempting to test a program in java and i am getting an array index out of bounds exception that i dont believe should be thrown. have a look at this code and tell me if im missing something? eclipse is telling me the error is being thrown in the location where i have added a comment to show it

class maze{

private int cols; // number of columns in maze  
private int rows; // number of rows in maze
private String name;
private weightedGraph<Integer> graph;
private dijkstra solution;
public char[][] mazeStore;

public maze(String filename){

    try{

        FileReader r = new FileReader(filename);
        Scanner s = new Scanner(r);
        this.rows = s.nextInt();
        this.cols = s.nextInt();
        this.name = filename;


        this.mazeStore = new char[(2*rows)+1][(2*cols)+1];
        String line = s.nextLine();
        for(int k = 0; k < ((2*rows)+1); k++){

            char[] temp = line.toCharArray();

            for(int i = 0; i < temp.length; i++){
                mazeStore[k][i] = temp[i];
                line = s.nextLine();
            }
        }



        graph = new weightedGraph<Integer>(rows*cols); 


        for(int y = 1; y < 2*rows; y++){
            for(int x = 1; x < 2*cols; x++){
                if((x % 2 == 1) && (y % 2 == 0)){
                    if(mazeStore[x][y] != '-'){ // <<<<<<<<<<<<<<THIS IS WHERE THE ERROR IS THROWN 
                        int label = (x - 1) + (x / 2);
                        graph.addEdge(label, label+cols, 1);
                        graph.addEdge(label+cols, label, 1);
                    }
                }

                if((x % 2 == 0) && (y % 2 == 1)){
                    if(mazeStore[x][y] != '|'){
                        int label = ((x - 1) + (x / 2)) + (y / 2);
                        graph.addEdge(label, label+1, 1);
                        graph.addEdge(label+1, label, 1);
                    }
                }
            }
        }



        this.solution = new dijkstra(graph, 0); 


    }
    catch(FileNotFoundException e){
        System.err.println("FileNotFoundException: " + e.getMessage());
    }

Answer 1

You initialized array

new char[(2*rows)+1][(2*cols)+1] 

but iterating it

for(int y = 1; y < 2*rows; y++){//y row iterator
    for(int x = 1; x < 2*cols; x++){//x col iterator

so it should be
mazeStore[y][x] not mazeStore[x][y]