Question

My question is boolean isLive = false; why is this assigned as false? I have seen very similer examples but I never quet understand it. could anyone explain what this line is doing?

/**
 * Method that counts the number of live cells around a specified cell

 * @param board 2D array of booleans representing the live and dead cells

 * @param row The specific row of the cell in question

 * @param col The specific col of the cell in question

 * @returns The number of live cells around the cell in question

 */

public static int countNeighbours(boolean[][] board, int row, int col)
{
    int count = 0;

    for (int i = row-1; i <= row+1; i++) {
        for (int j = col-1; j <= col+1; j++) {

            // Check all cells around (not including) row and col
            if (i != row || j != col) {
                if (checkIfLive(board, i, j) == LIVE) {
                    count++;
                }
            }
        }
    }

    return count;
}

/**
 * Returns if a given cell is live or dead and checks whether it is on the board
 * 
 * @param board 2D array of booleans representing the live and dead cells
 * @param row The specific row of the cell in question
 * @param col The specific col of the cell in question
 * 
 * @returns Returns true if the specified cell is true and on the board, otherwise false
 */
private static boolean checkIfLive (boolean[][] board, int row, int col) {
    boolean isLive = false;

    int lastRow = board.length-1;
    int lastCol = board[0].length-1;

    if ((row >= 0 && row <= lastRow) && (col >= 0 && col <= lastCol)) {             
        isLive = board[row][col];
    }

    return isLive;
}

Answer 1

That’s simply the default value, which may be changed if the test (if clause) is verified.

It defines the convention that cells outside the board aren’t live.

This could have been written as :

private static boolean checkIfLive (boolean[][] board, int row, int col) {

    int lastRow = board.length-1;
    int lastCol = board[0].length-1;

    if ((row >= 0 && row <= lastRow) && (col >= 0 && col <= lastCol)) {             
        return board[row][col];
    } else {
        return false;
    }
}