CodeGym/Help with Java Tasks/Why third requirement isn't met

Level 23

Beersheba

09.12.2019
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Why third requirement isn't met

Question about the task

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I don't understand why countMineNeighbors method doesn't count mined neighbors for every non mined cell in the gameField matrix??

Now let's count the mines in adjacent cells. To do this, we'll add a field to each cell of the matrix, which will be responsible for the number of mined neighbors. First, we find all the neighbors, and then we count how many of them are mined.

To get the list of neighbors, you now have the getNeighbors() method, which has one GameObject (cell) parameter.

Your task is to, in a separate method, count the number of mined neighbors for each cell in gameField and assign this value to the appropriate field of the cell.

Although your work is not visible (you started program to see what happens, right?), it is very important to future steps.

Requirements:

The GameObject class must have a public int countMineNeighbors field.
The MinesweeperGame class must have a private void countMineNeighbors() method.
The countMineNeighbors() method should, for each non-mined cell in the gameField matrix, count the number of adjacent mined cells and assign this value to the countMineNeighbors field.
The countMineNeighbors() method should use the getNeighbors(GameObject gameObject) method.
In the createGame() method, after all the elements of the gameField matrix are created, the countMineNeighbors() method must be called.

package com.codegym.games.minesweeper; import java.util.List; public class GameObject { public int x; public int y; public boolean isMine; public int countMineNeighbors; GameObject(int x, int y, boolean isMine){ this.x = x; this.y = y; this.isMine = isMine; } }

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yehuda b

Level 23 , Beersheba, Israel

10 December 2019, 13:10

I changed lines 57 & 58 to: for(GameObject g:getNeighbors(gameField[i][j])){ if(g.isMine) gameField[i][j].countMineNeighbors++; took it from: https://codegym.cc/help/5137 and it worked, though don't know why it's better.....

yehuda b

Level 23 , Beersheba, Israel

10 December 2019, 13:55

OK, so I just now realized that the reason why lines 57 & 58 weren't meeting third condition was because they counted ALL the neighbors (not only the mined ones). Though I didn't think that that was the problem, because the message from the mentor was: "be sure that for each non-mine element of the gameField matrix the countMineNeighbors() method counts the number of adjacent mined cells.", so I thought (mistakenly) that something was wrong with lines 55 & 56 (for loops). What further confused me, was that I thought that lines 45 & 46 from getNeighbors method was there to stop a non-mined neighbor from entering the result List (which is impossible because == will return false if each operand refers to a different memory location, thus causing ALL neighbors to enter the List), whereas in truth it's there to stop "itself"(the parameter index) from entering the List, a step which IMHO isn't required (edit: it is absolutely necessary for later tasks!) , as " if(g.isMine) " will prevent it from counting itself as a mine, though you could argue that in principle you want the getNeighbors method only to get neighbors. Hope others will find this question and comments useful.

Gabriella LaPlace

Level 16 , Basseterre, Saint Kitts and Nevis

28 February 2020, 15:35

I tried your code and changed line 57 to 58; and the 3rd condition is still not working.

yehuda b

Level 23 , Beersheba, Israel

29 February 2020, 21:25

Can you describe why you think doesn't validate, or post your code? I think though I made a mistake, don't change line 57, you still need that condition, on line 58 do the code from my first comment, Hope I'm right as I did this task quite a while ago.

Gabriella LaPlace

Level 16 , Basseterre, Saint Kitts and Nevis

1 March 2020, 12:37

I tried to do what you said but it isn't working. I actually just use the help section to solve this mine game, and then read over the code, but I've been confused.

package com.codegym.games.minesweeper;

import com.codegym.engine.cell.Color;
import com.codegym.engine.cell.Game;

import java.util.ArrayList;
import java.util.List;

public class MinesweeperGame extends Game {
    private static final int SIDE = 9;
    private GameObject[][] gameField = new GameObject[SIDE][SIDE];
    private int countMinesOnField;

    @Override
    public void initialize() {
        setScreenSize(SIDE, SIDE);
        createGame();
    }

    private void createGame() {
        for (int y = 0; y < SIDE; y++) {
            for (int x = 0; x < SIDE; x++) {
                boolean isMine = getRandomNumber(10) < 1;
                if (isMine) {
                    countMinesOnField++;
                }
                gameField[y][x] = new GameObject(x, y, isMine);
                setCellColor(x, y, Color.ORANGE);

            }
        }
        countMineNeighbors();
    }

    private List<GameObject> getNeighbors(GameObject gameObject) {
        List<GameObject> result = new ArrayList<>();
        for (int y = gameObject.y - 1; y <= gameObject.y + 1; y++) {
            for (int x = gameObject.x - 1; x <= gameObject.x + 1; x++) {
                if (y < 0 || y >= SIDE) {
                    continue;
                }
                if (x < 0 || x >= SIDE) {
                    continue;
                }
                if (gameField[y][x] == gameObject) {
                    continue;
                }
                result.add(gameField[y][x]);
            }
        }
        return result;
    }

Gabriella LaPlace

Level 16 , Basseterre, Saint Kitts and Nevis

1 March 2020, 12:37

private void countMineNeighbors() {
        for (int i = 0; i < SIDE; i++) {
            for (int j = 0; j < SIDE; j++) {
                if (!gameField[i][j].isMine) {
                         gameField[i][j].countMineNeighbors++ ;
                }
            }
        }
    }
}

yehuda b

Level 23 , Beersheba, Israel

30 March 2020, 14:01

Hi! was out of doing java 4 a while so sorry 4 not replying, why don't u do:

private void countMineNeighbors() {
      for (int i = 0; i < SIDE; i++) {
            for (int j = 0; j < SIDE; j++) {
                if (!gameField[i][j].isMine) {
for(GameObject g:getNeighbors(gameField[i][j])){
                        if(g.isMine)
                            gameField[i][j].countMineNeighbors++;
}
 }
   }
    }
}

sorry that the code isn't aligned well, I think in your code above u just added to countMineNeighbors +1 for every non mined cell, again sorry 4 late reply hope its still helps (or better if u got the task done already :-))

Gabriella LaPlace

Level 16 , Basseterre, Saint Kitts and Nevis

30 March 2020, 15:14

It's okay if you stopped a while. I tried your code but requirement 3 is not working. Also, I don't even understand this game, I started to get lost a while back.

yehuda b

Level 23 , Beersheba, Israel

14 April 2020, 13:44

Ok, sorry for not replying earlier but if it still interests you I'll try to figure it out in the coming days as tonight is a holiday for me, I was still out of java for the time being with all the virus craziness (I have 3 kids under 5 @ home) but I do want to continue after the holiday and one of the most satisfying parts of programming for me, is interacting with other people and coming up with solutions to problems and being able to explain them, so if u can still benefit (I see ur on level 15 already) I'll try to go through the game and the tasks (of the minesweeper game) again in the coming days