I'm creating a textbased noughts and crosses game in java and want to determine winning situations. I have used an array for the board such as String [] board :-
[0][1][2]
[3][4][5]
[6][7][8]
I have a whole list of possibilities that checks if 3 values in a row are the same in if statements.
This is an example of what i have:
if ((board [0] != "" && board [0] == board [1] && board [1] == board [2])) {
return true
}
Is there a way that does the same thing with a less amount of code?
Thanks
Your idea can be made sound either by
.equals() instead of == if you are really storing strings, or== is safe.Now if you are really making a noughts and crosses game, you have 8 different winning conditions, which, if you grow your current style of coding will have the form (here I am assuming characters, not strings):
winner =
(b[0] != ' ' && b[0] == b[1] && b[1] == b[2]) ||
(b[3] != ' ' && b[3] == b[4] && b[4] == b[5]) ||
...
(b[0] != ' ' && b[0] == b[4] && b[4] == b[8]);
There are other ways to do this; I'm sure a google search for tic-tac-toe or naughts and crosses implementations will show you quite a few.
If you would like to get fancy, there is a well-known technique of "labeling" each cell with a power of two. Then by adding up the scores (i.e., looking at the player's bit vector) and doing a binary AND on the set of eight winning conditions you can determine a winning position in one shot.
Here is a comment block for a tic-tac-toe game that illustrates the technique. (You didn't ask for actual code, so I'm withholding that from the answer):
/*
* To determine a win condition, each square is "tagged"
* from left to right, top to bottom, with successive
* powers of 2. Each cell thus represents an individual
* bit in a 9-bit string, and a player's squares at any
* given time can be represented as a unique 9-bit value.
* A winner can thus be easily determined by checking
* whether the player's current 9 bits have covered any
* of the eight "three-in-a-row" combinations.
*
* 273 84
* \ /
* 1 | 2 | 4 = 7
* -----+-----+-----
* 8 | 16 | 32 = 56
* -----+-----+-----
* 64 | 128 | 256 = 448
* =================
* 73 146 292
*
*/
var wins = [7, 56, 448, 73, 146, 292, 273, 84];
This was JavaScript. For Java, use
private static final int[] WINS = new int[]{7, 56, 448, 73, 146, 292, 273, 84};
Apologies if the binary logic approach here is not what you want; I thought it would be a good place to show it off though, in case others land on this page.
How are you storing your data? As Strings? "X" and "O"? or as numbers? 0, 1?
Like others said if you use Strings (an object) the == operator will not work!. You'd want to use board[0].equals(....) for == and !board.equals(...) for !=.
Having said that, using Strings is really not flexable for testing scenarios. I did tic-tac-toe in highschool so I know your pain. Using copy & paste it really doesn't take that long to write a large if-statement to check all rows/columns/diagnals. Five or ten minutes tops.
If you're more interested in compact code you might want to consider using numbers since you can use math to check conditions...
if (row is not empty) and
((sum of indexes in row == 3) player 1 wins) or
(sum of indexes in row == 0) player 2 wins
)
Get the idea?
Also, one tip I would suggest is using a two dimensional array (String[][]) so you can check on rows/columns easier!
==on strings really means in Java....