Java 2D阵列网格

Question

So basically I am trying to make a 9x9 grid for a minesweeper game. I need the grid to be filled with question marks to represent a minefield that has not been selected yet. Ex: [?][?][?][?][?] Basically my question is how would I get my program to output an array of question marks like that?

import java.util.Scanner;
import java.util.Arrays;

public class H4_Minesweeper {

    public static void main(String[] args) {
        //Game Description and rules
        System.out.println("Minesweeper is a very straightforward game, the rules are simple.");
        System.out.println("Uncover a mine (x), and the game ends. Uncover an empty square (o), and you keep playing.");
        System.out.println("A question mark (?) will represent tiles you have not uncovered yet.");
        System.out.println("Uncover a number, and it tells you how many mines lay hidden in the eight surrounding squares.");
        System.out.println("Use this information to carefully choose which squares to click.");
        System.out.println("\n\n\n");

        Scanner userin;


        String[][] board = new String [9][9];
        for (int r = 0; r<board.length;r++){
            for (int c = 0; c <board.length;c++){

            }
        }
    }
}     

Answer 1

First, you must initialize the array by setting all its elements to "?" :

String[][] board = new String [9][9];
for (int r = 0; r<board.length;r++){
    for (int c = 0; c <board.length;c++){
        board[r][c] = "?";
    }
}

Then you can print it:

for (int r = 0; r<board.length;r++){
    for (int c = 0; c <board.length;c++){
        System.out.print (board[r][c] + " ");
    }
    System.out.println();
}

Answer 2

This should do it.

for (int r = 0; r<board.length;r++){
   for (int c = 0; c <board.length;c++){
      board[r][c] = "?";  // Initialize the cell
      System.out.print("[" +board[r][c] + "]"); // Display the content of cell board
   }
   System.out.println();  // go to next line
}

Answer 3

Fill your 2d array with the String "?" for each of the grid spaces, and then, go row by row printing out the values of each array index

Filling array:

String[][] board = new String[9][9];

for(int y=0;y<9;y++){
    for(int x=0;x<9;x++){
        board[x][y] = "?";
    }
}

Displaying the rows:

for (int r = 0; r<9;r++){
    String line = "";
    for (int c = 0; c <9;c++){
        line+="["+board[c][r]+"]";
    }
    System.out.println(line);
}