How to display array elements?

Question

So I am trying to write a method that populate a board in a game. I am just beginning to learn about programming so I do not know much about special methods.

public static void Board(char[][] array){

  for(int i=0; i<2*array.length+1; i++) {
  if(i %2 ==0){
    for(int j=0; j<2*array.length+1;j++){
      if(j%2==0){
        System.out.print("+");
      }
      else{
        System.out.print("-");
      }
    }
  }
  else {
      for(int j=0; j<2*array.length+1;j++){
        if(j%2==0){
          System.out.print("|");
        }
        else{
          System.out.print(" "); // Maybe should use this spot to insert the x and o from the array.
        }
  }
    }
  System.out.println();

But in the board, where I currently have empty spaces, I want to actually be able to accept input.

For example , if

char [][] b={{'',' x',' ',},{' ','s','t '},{'o','o',' '}};
 Board(a);

Then instead of only having the empty spaces, I would like the element corresponding to the array to go there. I marked on my code where I think this might be done. I don't know of any special methods, but possibly DeepArray to string or such. I understand how to import using Arrays.ToString, the issue is with the index.

If your goal is to provide custom formatting, please detail how you want the output to look. Otherwise it's really hard to guess from your code. — markspace, Oct 31 '17 at 22:51
You're almost there. Replace `print(" ")` with `print(array[i/2][j/2])`. — Andreas, Oct 31 '17 at 22:55
While I'm sure Andreas is correct, your code is completely insane at this point. Even though you might see twice as many characters on a line as array elements, the **index** of the array should never use `x<2*array.length+1`. Just use the normal number of elements in the array, *don't* divide by 2 as suggested, and your code will look a lot cleaner and be easier to understand (esp. for you). — markspace, Oct 31 '17 at 23:01

score 1 · Accepted Answer · answered Oct 31 '17 at 23:13

As mentioned in a comment, you're almost there:
Replace print(" ") with print(array[i/2][j/2]).

That will then make the code print correct output, after also fixing the errors in the two lines of code calling the method:

char[][] b={{' ','x',' '},
            {' ','s','t'},
            {'o','o',' '}};
Board(b);

Output

+-+-+-+
| |x| |
+-+-+-+
| |s|t|
+-+-+-+
|o|o| |
+-+-+-+

To followup on comment by @markspace, your code can be simplified like this:

public static void printBoard(char[][] board) {
    StringBuilder line = new StringBuilder();
    for (int i = 0; i < board[0].length; i++)
        line.append("+-");
    String rowSeparatorLine = line.append('+').toString();
    System.out.println(rowSeparatorLine);
    for (char[] row : board) {
        line.setLength(0); // clear
        for (char cell : row)
            line.append('|').append(cell);
        System.out.println(line.append('|').toString());
        System.out.println(rowSeparatorLine);
    }
}

The code uses a StringBuilder to build a whole line in memory before printing it, e.g. so it only has to build the row separator line once.

It also uses enhanced for loops to keep the code simpler.

I also fixed the method name. Java naming convention is for method names to start with lowercase letter, and should usually start with a verb, since the method is actually intended to do something.

How to display array elements?

1 Answers1