2D array Null Pointer Exception error - java

public class DoubleMatrix
{
private double[][] doubMatrix;
public DoubleMatrix(int row, int col)
{
if(row > 0 && col > 0)
{
makeDoubMatrix(row,col);
}
else
{
row = 1;
col = 1;
}
}
public DoubleMatrix(double[][] tempArray)
{
if(tempArray != null)
{
for(int i = 0; i < tempArray.length-1;i++)
{
if(tempArray[i].length == tempArray[i+1].length)
{
tempArray = doubMatrix;
}
}
}
else
{
makeDoubMatrix(1,1);
}
}
public int getDim1()
{
return doubMatrix.length;
}
public int getDim2()
{
return doubMatrix[0].length;
}
private void makeDoubMatrix(int row, int col)
{
double[][] tempArray = new double[row][col];
for (int i = 0;i < row;i++)
{
for(int j = 0;j < col;j++)
{
tempArray[i][j] = Math.random() * (100);
doubMatrix[i][j] = tempArray[i][j];
}
}
}
public DoubleMatrix addMatrix(DoubleMatrix secondMatrix)
{
//this. doubMatrix = doubMatrix;
double[][] tempArray;
if(secondMatrix.doubMatrix.length == doubMatrix.length)
if(secondMatrix.doubMatrix[0].length == doubMatrix[0].length)
{
tempArray = new double[doubMatrix.length][doubMatrix[0].length];
for(int i = 0; i< secondMatrix.doubMatrix.length;i++)
for(int j = 0; j< secondMatrix.doubMatrix[i].length;j++ )
{
tempArray[i][j] = secondMatrix.doubMatrix[i][j] + doubMatrix[i][j];// add two matrices
}//end for
return new DoubleMatrix (tempArray);
}
return new DoubleMatrix(1,1);
}
public DoubleMatrix getTransposedMatrix()
{
double[][] tempArray = new double[doubMatrix.length][doubMatrix[0].length];
for(int i = 0;i < doubMatrix.length;i++)
for(int j = 0;j < doubMatrix[i].length;j++)
{
tempArray[j][i] = doubMatrix[i][j];// transposed matrix2
}//end for
return new DoubleMatrix(tempArray);
}
public DoubleMatrix multiplyingMatrix(DoubleMatrix secondMatrix)
{
double[][] tempArray = new double[secondMatrix.doubMatrix.length][doubMatrix[0].length];
//check if dimension of matrix1 equal to dimension of matrix2
if(secondMatrix.doubMatrix[0].length == doubMatrix.length)
if(doubMatrix.length == secondMatrix.doubMatrix[0].length)
{
for (int i = 0; i <secondMatrix.doubMatrix.length; i++)
{
for(int j = 0; j < doubMatrix[0].length; j++)
{
for (int k = 0; k < doubMatrix.length; k++)
{
tempArray[i][j] = tempArray[i][j] + secondMatrix.doubMatrix[i][k]*doubMatrix[k][j]; // multiply 2 matrices
}
}
}//end for
}// end if
return new DoubleMatrix(1,1);
}
public void printMatrix(String text)
{
System.out.println(text);// output string
for(int i = 0; i< doubMatrix.length;i++)
{
for(int j = 0; j< doubMatrix[i].length;j++ ) {
System.out.printf("%9.1f", doubMatrix[i][j]);// out put value for matrices
}
System.out.println();
}
}
}
public class Program3
{
public static void main(String[] args)
{
int num1 = (int) (Math.random()*(10-3+1)+3);
int num2 = (int) (Math.random()*(10-3+1)+3);
DoubleMatrix doubMatObj1 = new DoubleMatrix(num1,num2);
DoubleMatrix doubMatObj2 = new DoubleMatrix(doubMatObj1.getDim1(),doubMatObj1.getDim2());
DoubleMatrix doubMatObj3;
doubMatObj2.getDim1();
doubMatObj3 = doubMatObj1.addMatrix(doubMatObj2);
doubMatObj1.printMatrix("First Matrix Object");
doubMatObj2.printMatrix("Second Matrix Object");
doubMatObj3.printMatrix("Result of Adding Matrix Objects");
doubMatObj2 = doubMatObj2.getTransposedMatrix();
doubMatObj2.printMatrix("Result of inverting Matrix Object");
doubMatObj3 = doubMatObj1.multiplyingMatrix(doubMatObj2);
doubMatObj3.printMatrix("Result of Multiplying Matrix Objects");
}
}
Hi, I have a NullPointerException error in the last line statement of the makeDoubMatrix method as well the call makedoubMatrix in side if statement of the first constructor.
doubMatrix seems to be null when I already initialize it. How will I be able to fix this problem ?

You want to initialize the array, i.e.:
private double[][] doubMatrix = new double[size1][size2];
where size1 and size2 are arbitrary sizes. What you probably want is:
if(row > 0 && col > 0)
{
doubMatrix = new double[row][col];
makeDoubMatrix(row,col);
}
else
{
doubMatrix = new double[1][1];
makeDoubMatrix(1,1);
}
which initializes the array doubMatrix to a size of row*col if both row and col are greather than 0, and to 1*1 otherwise, then calls makeDoubMatrix with its initialized size (you could have this method call after the if-else, using doubMatrix.size and doubMatrix[0].size, but I think it's more readable now).
Change the second constructor (which takes a 2D array) using the same reasoning.

You're not initializing doubMatrix. The only line which assigns a value to doubMatrix is this commented out one:
//this. doubMatrix = doubMatrix;
(And that wouldn't help.)
Ask yourself where you think you're initializing it - where do you think you've got something like:
doubMatrix = new double[1][2];
... or an assignment copying a value from another array:
doubMatrix = someOtherVariable;
If you haven't got any statements assigning it a value, you aren't initializing it, so it will always have the default value of null.

Related

Determining vectors array length

public class Matrix {
public static int a = 0;
public static int b = 0;
public double myArray[][];
public Matrix(double a[][]) {
this.myArray = a;
}
public Matrix(int b, Vector... vectors) {
double myArray[][] = new double[vectors.length][];
int row = vectors.length;
Matrix.a = row;
int column = vectors[0].getYourArray().length;
Matrix.b = column;
for (int i = 0; i < row; i++) {
myArray[i] = new double[row];
}
for (int i = 0; i < row; i++) {
for (int j = 0; j < column; j++) {
if (b == 0) {
double[] a = vectors[i].getYourArray();
myArray[i][j] = a[j];
} else {
myArray[j][i] = vectors[i].getYourArray()[j];
}
}
}
}
public class Vector {
double yourArray[];
public double[] getYourArray() {
return yourArray;
}
public void setYourArray(double[] yourArray) {
this.yourArray = yourArray;
}
public Vector(double... yourArray) {
this.yourArray = yourArray;
}
}
}
I create 2 vectors array and send them into vector class to make an array which includes these two vectors parameters and then send to matrix class to create matrices with dimension of vector arrays
The problem is that how can i determine the rows and columns of new matrix?
I cannot write a proper code guys please help me
As you see it in your code:
1-th dimension: vectors.length
2-th dimension: vectors[0].getYourArray().length
Normally you also have to ensure, that for all vectors[0].getYourArray() the length is the same.

Creating a matrix of ArrayList<byte[]> and rotating it

So I'm creating many byte[] that I would like to be placed in a matrix, eg. 3x3, so 9 byte[] which I can then by using the methods below rotate them accordingly.
// ARRAY LIST
private static void transpose(ArrayList<byte[]> m) {
for (int i = 0; i < m.size(); i++) {
for (int j = i; j < m.get(0).length; j++) {
byte x = m.get(i)[j];
m.get(i)[j] = m.get(j)[i];
m.get(j)[i] = x;
}
}
}
public static void swapRows(ArrayList<byte[]> m) {
for (int i = 0, k = m.size() - 1; i < k; ++i, --k) {
byte[] x = m.get(i);
m.set(i, m.get(k));
m.set(k, x);
}
}
public static void rotateByNinetyToLeft(ArrayList<byte[]> m) {
transpose(m);
swapRows(m);
}
public static void rotateByNinetyToRight(ArrayList<byte[]> m) {
swapRows(m);
transpose(m);
}
When I call the inserts method I want to add to the array in the correct position. So from 0,0 then 0,1 then 1,1 .... 3,3. So I created the code to do that with..
public void inserts(byte[] s){
if(x ==y){
buffer.get(x)[y]= s;
System.out.println(y);
y++;
}
else{
buffer.get(x)[y]= s;
System.out.println(x);
x++;
}
counter++;
}
But It won't allow me to execute the insertion properly. Unsure as to what is the problem.
Kind of feel like i'm making a very blatant mistake, any help would be great
thank you
EDIT:
code for array of arrays:
private static void transposeb(byte[][] m) {
for (int i = 0; i < m.length; i++) {
for (int j = i; j < m[0].length; j++) {
byte x = m[i][j];
m[i][j] = m[j][i];
m[j][i] = x;
}
}
}
public static void swapRowsb(byte[][] m) {
for (int i = 0, k = m.length - 1; i < k; ++i, --k) {
byte[] x = m[i];
m[i] = m[k];
m[k] = x;
}
}
public static void rotateByNinetyToLeftb(byte[][] m) {
transposeb(m);
swapRowsb(m);
}
public static void rotateByNinetyToRightb(byte[][] m) {
swapRowsb(m);
transposeb(m);
}
and insertion
private byte[][] buffer;
private int x=0;
private int y=0;
public FixedBuffer(int BUFF_SIZE) {
this.BUFF_SIZE = BUFF_SIZE;
buffer = new byte[BUFF_SIZE][BUFF_SIZE];
}
public void inserts(byte[] s){
if(x ==y){
buffer.get(x)[y]= s;
System.out.println(y);
y++;
}
else{
buffer.get(x)[y]= s;
System.out.println(x);
x++;
}
counter++;
}
Say we have a vector of 3 x 3
I want to use inserts() to add all the byte[], there will be 9 in total. so 9 byte[], each time I add one the index's (x and y) change.
Structure:
byte[], byte[], byte[]
byte[], byte[], byte[]
byte[], byte[], byte[]
Some test code first.
ArrayList<byte[]> arr = new ArrayList<byte[]>(9);
initialize(arr);
printRows(arr);
arr = transpose(arr);
printRows(arr);
Initialize ArrayList with random test data
private static void initialize(ArrayList<byte[]> arr) {
for(byte i = 0 ; i < 9 ; i++) {
byte[] a = {i,i,i,i};
arr.add(a);
}
}
A way to find out if all the ops are working as required.
private static void printRows(ArrayList<byte[]> arr) {
int row = 0;
for(int i = 0 ; i < arr.size() ; i++) {
System.out.print(Arrays.toString(arr.get(i)) + " ");
row++;
if(row%3 == 0)
System.out.println();
}
System.out.println("\n\n");
}
The method to transpose. Took the hacky way of making a new ArrayList. Please change that. This is just to demonstrate the logic.
private static ArrayList<byte[]> transpose(ArrayList<byte[]> arr) {
ArrayList<byte[]> newArr = new ArrayList<byte[]>(9);
// fill with null
for(int i = 0 ; i < 9 ; i++)
newArr.add(null);
for(int row = 0; row < 3 ; row++) {
for(int col = 0 ; col < 3 ; col++) {
// diagonal
if(row == col) {
newArr.add(row + 3*col, arr.get(row + 3*col));
}
int second = row + 3*col; // elem at (row,col)
int first = 3*row + col; // elem at (col,row)
// swap
newArr.set(first, arr.get(second));
newArr.set(second, arr.get(first));
}
}
return newArr;
}

Null Pointer Exception Error in a DoubleMatrix class [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 7 years ago.
I'm having trouble with a java problem. I get this error:
Exception in thread "main" java.lang.NullPointerException
at DoubleMatrix.getDim1Size(DoubleMatrix.java:28)
at Program3.main(Program3.java:16)
I don't understand where it is null
public class DoubleMatrix
{
private double[][] doubMatrix;
public DoubleMatrix(int firstDim, int secondDim, double upperLimit)
{
if(firstDim > 0 && secondDim > 0 && upperLimit > 0){
firstDim = 1;
secondDim = 1;
upperLimit = 1;
}
}
public DoubleMatrix(double[][] tempArray)
{
if(tempArray != null && tempArray.length != 0){
for(int i =0; i < tempArray.length; i++) {
doubMatrix = tempArray;
}
}
else{
tempArray = new double[1][1];
}
}
public int getDim1Size(){
int firstDim1 = doubMatrix.length;
return firstDim1;
}
public int getDim2Size(){
int secondDim1 = doubMatrix[0].length;
return secondDim1;
}
private void makeDoubMatrix(int firstDim, int secondDim, double upperLimit){
double[][] randomMatrix = new double[firstDim][secondDim];
for(int row = 0; row < doubMatrix.length; row++) {
for(int column = 0; column < doubMatrix[row].length; column++){
doubMatrix[row][column] = (double)(Math.random() * 100);
}
}
}
public DoubleMatrix addMatrix(DoubleMatrix arrayObj)
{
if(doubMatrix.length == arrayObj.doubMatrix.length && doubMatrix[0].length == arrayObj.doubMatrix[0].length){
double[][] TotalTwoDimArray = new double[doubMatrix.length][doubMatrix[0].length];
for(int row = 0; row < TotalTwoDimArray.length; row++){
for(int column = 0; column < TotalTwoDimArray[row].length; column++){
TotalTwoDimArray[row][column] = doubMatrix[row][column] + arrayObj.doubMatrix[row][column];
}
}
return new DoubleMatrix(TotalTwoDimArray);
}
return new DoubleMatrix(1, 1, 1);
}
public DoubleMatrix getTransposedMatrix(){
double[][] TransMatrix = new double[doubMatrix[0].length][doubMatrix.length];
for(int row = 0; row < doubMatrix.length; row++){
for(int column = 0; column < doubMatrix[row].length; column++){
TransMatrix[row][column] = doubMatrix[column][row];
}
}
return new DoubleMatrix(TransMatrix);
}
public DoubleMatrix multiplyMatrix(DoubleMatrix obj1)
{
if(doubMatrix[0].length == obj1.doubMatrix.length){
double[][] multipliedMatrix = new double[doubMatrix.length][obj1.doubMatrix[0].length];
for(int i = 0; i < multipliedMatrix.length; i++){
for(int j = 0; j < multipliedMatrix[i].length; j++){
for(int k = 0; k < doubMatrix[0].length; k++){
multipliedMatrix[i][j] = doubMatrix[i][k] * obj1.doubMatrix[k][j] + multipliedMatrix[i][j];
}
}
}
return new DoubleMatrix(multipliedMatrix);
}
return new DoubleMatrix(1, 1, 1);
}
public void printMatrix(String titles){
System.out.println(titles);
for(int row = 0; row < doubMatrix.length; row++){
for(int column = 0; column < doubMatrix[row].length; column++){
System.out.printf("%9.1f", doubMatrix[row][column]);
}
System.out.println();
}
}
}
// main in different class
public class Program3
{
public static void main(String[] args)
{
DoubleMatrix doubMatObj1;
DoubleMatrix doubMatObj2;
DoubleMatrix doubMatObj3;
int max = 10;
int min = 3;
int firstDim = (int)(Math.random() * (max - min + 1) + min);
int secondDim = (int)(Math.random() * (max - min + 1) + min);
doubMatObj1 = new DoubleMatrix(firstDim, secondDim, 100.);
doubMatObj2 = new DoubleMatrix(doubMatObj1.getDim1Size(), doubMatObj1.getDim2Size(), 100.);
doubMatObj3 = doubMatObj1.addMatrix(doubMatObj2);
doubMatObj1.printMatrix("First Matrix Object");
doubMatObj2.printMatrix("Second Matrix Object");
doubMatObj3.printMatrix("Result of Adding Matrix Objects");
doubMatObj2.printMatrix("Result of Transposing Matrix Object");
doubMatObj1.multiplyMatrix(doubMatObj2);
doubMatObj3.printMatrix("Result of Multiplying Matrix Objects");
}
}
In java, non primitives don't get initialized by just declaring them. So if you get a NullPointerException in a line like foo.bar(), you know that foo had to be null. In your case you have doubMatrix.length, which indicates that doubMatrix has never been initialized. Looking at your code, only the second constructor ever initializes that variable, so calling the first constructor will leave doubMatrix==null to always be true.
I hope that is enough info to help you fix your problem yourself (and similar problems in the future), but I am not going to post a working code example, since fixing your code yourself will be a good exercise!
On a sidenote, in your second constructor you have:
for(int i =0; i < tempArray.length; i++) {
doubMatrix = tempArray;
}
If tempArray.length is for example 5, you would assign the same value 5 times to the same variable. I don't know what you are trying to do there, but it is certainly not what you had in mind.

IF Statement Checking (Not Working Properly)

randomEmpty() returns a random coordinate on the n x n grid that is empty (Method works). randomAdjacent() uses randomEmpty() to select an EMPTY coordinate on the map. Comparisons are then made to see if this coordinate has an VALID adjacent coordinate that is NON-EMPTY. The PROBLEM is that randomAdjacent does not always return the coordinates of space with an adjacent NON-EMPTY space. It will always return valid coordinates but not the latter. I can't spot the problem. Can someone help me identify the problem?
public int[] randomEmpty()
{
Random r = new Random();
int[] random = new int[2];
int row = r.nextInt(array.length);
int column = r.nextInt(array.length);
while(!(isEmpty(row,column)))
{
row = r.nextInt(array.length);
column = r.nextInt(array.length);
}
random[0] = row+1;
random[1] = column+1;
return random;
}
public int[] randomAdjacent()
{
int[] adjacentToX = new int[8];
int[] adjacentToY = new int[8];
int[] adjacentFrom = randomEmpty();
int count;
boolean isTrue = false;
boolean oneAdjacentNotEmpty = false;
while(!(oneAdjacentNotEmpty))
{
count = 0;
if(validIndex(adjacentFrom,1,-1))
{
adjacentToX[count] = adjacentFrom[0]+1;
adjacentToY[count] = adjacentFrom[1]-1;
count++;
}
if(validIndex(adjacentFrom,0,-1))
{
adjacentToX[count] = adjacentFrom[0];
adjacentToY[count] = adjacentFrom[1]-1;
count++;
}
if(validIndex(adjacentFrom,-1,-1))
{
adjacentToX[count] = adjacentFrom[0]-1;
adjacentToY[count] = adjacentFrom[1]-1;
count++;
}
if(validIndex(adjacentFrom,-1,0))
{
adjacentToX[count] = adjacentFrom[0]-1;
adjacentToY[count] = adjacentFrom[1];
count++;
}
if(validIndex(adjacentFrom,-1,1))
{
adjacentToX[count] = adjacentFrom[0]-1;
adjacentToY[count] = adjacentFrom[1]+1;
count++;
}
if(validIndex(adjacentFrom,0,1))
{
adjacentToX[count] = adjacentFrom[0];
adjacentToY[count] = adjacentFrom[1]+1;
count++;
}
if(validIndex(adjacentFrom,1,1))
{
adjacentToX[count] = adjacentFrom[0]+1;
adjacentToY[count] = adjacentFrom[1]+1;
count++;
}
if(validIndex(adjacentFrom,1,0))
{
adjacentToX[count] = adjacentFrom[0]+1;
adjacentToY[count] = adjacentFrom[1];
count++;
}
for(int i = 0; i < count; i++)
{
if(!(isEmpty(adjacentToX[i],adjacentToY[i])))
{
oneAdjacentNotEmpty = true;
isTrue = true;
}
}
if(isTrue)
break;
else
adjacentFrom = randomEmpty();
}
return adjacentFrom;
}
public boolean validIndex(int[] a,int i, int j)
{
try
{
Pebble aPebble = array[a[0]+i][a[1]+j];
return true;
}
catch(ArrayIndexOutOfBoundsException e)
{
return false;
}
}
public void setCell(int xPos, int yPos, Pebble aPebble)
{
array[xPos-1][yPos-1] = aPebble;
}
public Pebble getCell(int xPos, int yPos)
{
return array[xPos-1][yPos-1];
}
JUNIT Test Performed:
#Test
public void testRandomAdjacent() {
final int size = 5;
final Board board2 = new Board(size);
board2.setCell(1, 1, Pebble.O);
board2.setCell(5, 5, Pebble.O);
int[] idx = board2.randomAdjacent();
int x = idx[0];
int y = idx[1];
boolean empty = true;
for (int i = x - 1; i <= x + 1; i++) {
for (int j = y - 1; j <= y + 1; j++) {
if ((i == x && j == y) || i < 1 || j < 1 || i > size || j > size) {
continue;
}
if (board2.getCell(i, j) != Pebble.EMPTY)
empty = false;
}
}
assertFalse(empty);// NEVER gets SET TO FALSE
assertEquals(Pebble.EMPTY, board2.getCell(x, y));
}
As for the answer: I got carried away optimizing your code for readability. I'd think it's most likely
if (board2.getCell(i, j) != Pebble.EMPTY)
empty = false;
causing the problem as getCell operates in 1-based coordinates, but i, j are in 0-based.
You should think about your logic overall. The way I see it, your code might never terminate as randomEmpty() could keep returning the same field over and over again for an undetermined period of time.
I took the liberty to recode your if-if-if cascade into utility method easier to read:
public boolean hasNonEmptyNeighbor(int[] adjacentFrom) {
for(int i = -1; i <= 1; ++i) {
for(int j = -1; j <= 1; ++j) {
if(validIndex(adjacentFrom, i, j) //Still inside the board
&& // AND
!isEmpty(adjacentFrom[0]+i //not empty
,adjacentFrom[1]+j)) {
return true;
}
}
}
return false;
}
Given my previous comment about random() being not the best of choices if you need to cover the full board, your main check (give me an empty cell with a non-empty neighbor) could be rewritten like this:
public void find() {
List<Point> foundPoints = new ArrayList<Point>();
for(int i = 0; i < Board.height; ++i) { //Assumes you have stored your height
for(int j = 0; j < Board.width; ++j) { //and your width
if(isEmpty(i, j) && hasNonEmptyNeighbor(new int[]{i,j})) {
//Found one.
foundPoints.add(new Point(i, j));
}
}
}
//If you need to return a RANDOM empty field with non-empty neighbor
//you could randomize over length of foundPoints here and select from that list.
}

Random generator does not work

i tried to implement a method to set up a board with an array of Cell object. the method then randomly place a new string "C10" over the "---" string. My class and main is below
public class Cell {
public int addSpaces;
public Cell() {
addSpaces = 0;
}
public Cell(int x) {
addSpaces = x;
}
public String toString() {
String print;
if (addSpaces == -10)
print = "C10";
else
print = "---";
return print;
}
}
import java.util.Random;
public class ChutesAndLadders {
Cell[] board = new Cell[100]; // Set array of Cell object
Random ran = new Random();
Cell s = new Cell();
public int Chut, Ladd;
public ChutesAndLadders() {
}
public ChutesAndLadders(int numChutes, int numLadders) {
Chut = numChutes;
Ladd = numLadders;
}
public void setBoard() {
for (int i = 0; i < board.length; i++)
board[i] = new Cell(); // board now has 100 Cell with toString "---"
for (int k = 1; k <= Chut; k++) {
int RanNum = ran.nextInt(board.length); // Randomly replace the
// toString
if (board[RanNum] == board[k])
this.board[RanNum] = new Cell(-10);
else
k--;
}
}
public void printBoard() { // method to print out board
int count = 0;
for (int i = 0; i < board.length; i++) {
count++;
System.out.print("|" + board[i]);
if (count == 10) {
System.out.print("|");
System.out.println();
count = 0;
}
}
}
public static void main(String[] args) {
ChutesAndLadders cl = new ChutesAndLadders(10, 10);
cl.setBoard();
cl.printBoard();
}
}
Instead of randomly placing C10 all over the board I got this output;
|---|C10|C10|C10|C10|C10|C10|C10|C10|C10|
|C10|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
|---|---|---|---|---|---|---|---|---|---|
can someone tell me what i did wrong? Thank you.
I'm not sure what your intention with this was in your for-loop:
if (board[RanNum] == board[k])
But it will cause your for-loop to, for each k, generate random numbers until it generates k, and then set that cell. So for k == 1, it will always set cell 1, cell 2 for k == 2, cell 3 for k == 3, etc.
I'm guessing you want to do something more like:
for (int k = 1; k <= Chut; k++) {
int RanNum = ran.nextInt(board.length);
if (board[RanNum].addSpaces == 0) // uninitialized
this.board[RanNum] = new Cell(-10);
else
k--;
}
EDIT:
As you probably realized from the comment + other answers, the above code is not particularly readable. Something like this should be better:
int chutCount = 0;
while (chutCount < Chut)
{
int randomNum = ran.nextInt(board.length);
if (board[randomNum].addSpaces == 0) // uninitialized
{
board[randomNum] = new Cell(-10);
chutCount++;
}
}
I'm not sure exactly what you want to achieve, but if you eliminate the if else in your inner setBoard loop then you should get random placement of C10.
Change this:
for (int k = 1; k <= Chut; k++) {
int RanNum = ran.nextInt(board.length); // Randomly replace the
// toString
if (board[RanNum] == board[k])
this.board[RanNum] = new Cell(-10);
else
k--;
}
To this:
for (int k = 1; k <= Chut; k++) {
int RanNum = ran.nextInt(board.length); // Randomly replace the
// toString
this.board[RanNum] = new Cell(-10);
}
I think you meant !=.
for (int k = 1; k <= Chut; k++) {
int ranNum = (int)(Math.random()*board.length);
if (board[ranNum] != board[k])
this.board[ranNum] = new Cell(-10);
else
k--;
}

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