Knight’s Tour random move picker not working

I am working on randomizing which move my knight takes in my knight’s tour code. For some reason though, my switch statement always goes to default, instead of executing a possible move. I know my possible moves methods work because I have separately ran firstMoveChoice() on it’s own and it worked. So I know the problem is with my random move picker, but I can’t seem to figure it out.

Thanks for your help and time in advance! It is really much appreciated as I have looked this problem over and cannot find the answer.

public class MoveKnight extends Moves {

public int[][] moveTheKnight() {

    Moves switchBetweenMoves = new Moves();
    switchBetweenMoves.startingLocation();

    while (knight != 64) {
        int randomMove = new Random().nextInt();
        switch (randomMove) {
            case 1:
                switchBetweenMoves.firstMoveChoice();
                break;

            case 2:
                switchBetweenMoves.secondMoveChoice();
                break;

            case 3:
                switchBetweenMoves.thirdMoveChoice();
                break;

            // other possible moves

            default:
                System.out.println("No more possible moves.");
                break;
        }
        break;
    }
    return board;
}
}

Here is the result of the above code:

1  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
No more possible moves.
BUILD SUCCESSFUL (total time: 0 seconds)

Here is my Main method:

public static void main(String[] args) {

    MoveKnight myKnight = new MoveKnight();
    myKnight.moveTheKnight();
}

Here is my ChessBoard class:

public class ChessBoard {

int[][] board;

public ChessBoard() {
    this.board = new int[8][8];
}
}

Here is firstMoveChoice()

public int[][] firstMoveChoice() {

System.out.println();

x += 1;
y += 2;

if (x >= board.length) { // this tests to make sure the knight does not move off the row
    System.out.println("Cannot move off board on x axisn");
    x -= 1;
    y -= 2;
    return board;
}
else if (y >= board.length) { // this tests to make sure the knight does not move off the column
    System.out.println("Cannot move off board on y axisn");
    x -= 1;
    y -= 2;
    return board;
}
else if (board[x][y] != 0) { // this prevents the knight from landing on a previously landed on square
    x -= 1;
    y -= 2;
    System.out.println("Cannot move onto a used squaren");
    return board;
}
else { // this moves the knight when the above statements are false
    board[x][y] = ++knight;
    System.out.println("This executed and the knight movedn");

    for(int[] row : board) {
        printRow(row);
    }

    if (knight == 64) {
        System.out.println("Knight has completed the tour");
        }

        return board;
    }
}

Here is thirdMoveChoice(): It is practically the same as all the others, except for the change in numbers for the different moves.

public int[][] thirdMoveChoice() {

System.out.println();

x += 2;
y -= 1;

if (x >= board.length) { // this tests to make sure the knight does not move off the row
    System.out.println("Cannot move off board on x axisn");
    x -= 2;
    y += 1;
    return board;
}
else if (y >= board.length) { // this tests to make sure the knight does not move off the column
    System.out.println("Cannot move off board on y axisn");
    x -= 2;
    y += 1;
    return board;
}
else if (board[x][y] != 0) { // this prevents the knight from landing on a previously landed on square
    x -= 2;
    y += 1;
    System.out.println("Cannot move onto a used squaren");
    return board;
}
else { // this moves the knight when the above statements are false
    board[x][y] = ++knight;
    System.out.println("This executed and the knight movedn");
}

for(int[] row : board) {
    printRow(row);
}

if (knight == 64) {
    System.out.println("Knight has completed the tour");
    return board;
}

return board;
}

Answer

It’s because random.nextInt() return a value between -2,147,483,648 and 2,147,483,647

you should use the random.nextInt(int n) that return a value between 0 inclusive and n exclusive

so replace

int randomMove = new Random().nextInt(); b

int randomMove = 1 + new Random().nextInt(3);

Also, you should assign new Random() to a field that would be reused.

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Answer