Unneeded return is necessary when utilizing recursion and restarting the application

Question

Unneeded return is necessary when utilizing recursion and restarting the application

Recently, I successfully recreated the 2048 game in Java, which was a pleasant surprise to me as I didn't expect to create something this "advanced."

During the game, when tiles are moved, a new square/tile/number needs to be generated. To find an available spot for the new tile, my code randomly selects a number between 0 and 15 (tiles are numbered from 0 to 15 using a multidimensional array with 4 columns and 4 rows). If the chosen spot is already occupied, the function recalls itself by returning the existing tile. In cases where the spot is unoccupied, I simply return a number that is not utilized later. Can you help me identify what am I doing wrong?

Another question I have is related to starting a new game. Currently, I reset all variables in the newGame() function. Is there a way to restart the application instead? I couldn't find any information on the website regarding this.

I would also appreciate feedback on whether I followed programming conventions and your overall thoughts on my approach to recreating this game for practice. Thank you for taking the time to review this.

Below is the code snippet:

// Code goes here

java css recursion javafx return

Answer 1

Answer №1

Just like in @RyanJ's comment, you can define the function newCell() with a return type of void:

private void newCell() {
    int x = (int)(Math.random() * 4);
    int y = (int)(Math.random() * 4);
    if (cell[x][y] != 0) {
        newCell();
    } else {
        cell[x][y] = twoOrFour();
    }
}

You could achieve the same result using a loop as well:

private void newCell() {
    int x ;
    int y ;
    do {
        x = (int)(Math.random() * 4);
        y = (int)(Math.random() * 4);
    } while (cell[x][y] != 0);
    cell[x][y] = twoOrFour();
}

However, both of these approaches have drawbacks as it may take a long time to find an empty space. In the recursive version, there is also a possibility of running into a StackOverflowException. A more effective solution would be to create a list of empty cells and randomly select one:

private void newCell() {
    List<Integer> availableCells = new ArrayList<>();
    for (int i = 0; i < 16; i++) {
        int x = i / 4 ;
        int y = i % 4 ;
        if (cell[x][y] == 0) {
            availableCells.add(i);
        }
    }
    int nextCell = availableCells.get((int)(Math.random() * availableCells.size()));
    cell[nextCell / 4][nextCell % 4] = twoOrFour();
}

Answer 2

Just like in @RyanJ's comment, you can define the function newCell() with a return type of void:

private void newCell() {
    int x = (int)(Math.random() * 4);
    int y = (int)(Math.random() * 4);
    if (cell[x][y] != 0) {
        newCell();
    } else {
        cell[x][y] = twoOrFour();
    }
}

You could achieve the same result using a loop as well:

private void newCell() {
    int x ;
    int y ;
    do {
        x = (int)(Math.random() * 4);
        y = (int)(Math.random() * 4);
    } while (cell[x][y] != 0);
    cell[x][y] = twoOrFour();
}

However, both of these approaches have drawbacks as it may take a long time to find an empty space. In the recursive version, there is also a possibility of running into a StackOverflowException. A more effective solution would be to create a list of empty cells and randomly select one:

private void newCell() {
    List<Integer> availableCells = new ArrayList<>();
    for (int i = 0; i < 16; i++) {
        int x = i / 4 ;
        int y = i % 4 ;
        if (cell[x][y] == 0) {
            availableCells.add(i);
        }
    }
    int nextCell = availableCells.get((int)(Math.random() * availableCells.size()));
    cell[nextCell / 4][nextCell % 4] = twoOrFour();
}

Unneeded return is necessary when utilizing recursion and restarting the application

Answer №1

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