Tic Tac Toe - Checking for a winner

[FrederikB]

Hello!

I am currently developing a little Tic Tac Toe game in Java (For Android)
And i am stuck, i want to "CheckForWinner();" but i can't really figure out how...

I am thinking something like: "foreach(Field in Fields)" and then check which has value of 1 and which has a value of 2 :-)


EDIT: I figured it out now, and i did like this:

public boolean isWon(int token) {
		for (int i = 0; i < 3; i++)
			if ((gameBoard[i][0] == token) && (gameBoard[i][1] == token)
					&& (gameBoard[i][2] == token)) {
				return true;
			}
 
		for (int j = 0; j < 3; j++)
			if ((gameBoard[0][j] == token) && (gameBoard[1][j] == token)
					&& (gameBoard[2][j] == token)) {
				return true;
			}
 
		if ((gameBoard[0][0] == token) && (gameBoard[1][1] == token)
				&& (gameBoard[2][2] == token)) {
			return true;
		}
 
		if ((gameBoard[0][2] == token) && (gameBoard[1][1] == token)
				&& (gameBoard[2][0] == token)) {
			return true;
		}
 
		return false;
	}

Thanks in advance!

- Frederik

[Norm]

Can you use an array for the board instead of 9 different variables? The array can hold references to the Field objects. That will reduce the number of if tests needed.

[FrederikB]

I probably could, but i dont know how

[Norm]

Can you explain where the problem is?
Defining an array
assigning values to the slots in an array
referencing the contents of a slot in an array

[FrederikB]

I am a little new to Java and haven't worked alot with arrays..
Please explain more and show some code :-)

[Norm]

Here is the tutorial for arrays:
Arrays (The Java™ Tutorials > Learning the Java Language > Language Basics)

I suggest you put the current code aside for now and write a simple program with arrays to learn how to use them.

[FrederikB]

I have used arrays before, not just alot so you want me to do like this?:

int[] gameBoard;
gameBoard = new int[9];

And then:

gameBoard[0] = 1;

To show that the field has been taken by Player 1?

[Norm]

Or use an array of Field objects:

Field[] theSquares = new Field[9];

Then assign each slot with a Field object;

Or define the array with existing the existing Field objects:

Field[] theSquares = {row1_field1, row1_field2, etc through 3 3};

[FrederikB]

I changed my sourcecode, how would i now check for a winner?

[Norm]

I don't think you are using the array like an array. The code is using the array's slots like 9 different variables with the same name and a unique suffix like: [5]

Try using a 2 dim array that you can use the row and field values as indexes into the array instead of that awful bunch of if statements.

[FrederikB]

Please explain more

- And with some code examples

[Norm]

Look at something like this:

if(gameboard[row][field] == 0) {
  theField[row][field].setImageDrawable(GetPlayer());
  gameboard[row][field] = curPlayer;
  changePlayer(); 
}

[FrederikB]

How would i create a gameBoard array with two []? (not sure what they are called.. )

[Norm]

int[][] gameboard = new int[3][3]; // define 2 dim gameboard array

[FrederikB]

Okay, now i have this :-)

private void ClickField(int row, int field) {
 
		if (gameBoard[row][field] == 0) {
			theField[row][field].img.setImageDrawable(GetPlayer());
			gameBoard[row][field] = curPlayer;
			ChangePlayer();
		}
 
		CheckForWinner();
 
	}

So how will i do the "theField[row][field].img.setImageDrawable(GetPlayer());"?

[Norm]

Define a 2 dim array: theField and fill it with ImageView objects.
It replaces the 9 variables like this: row1_field1_img

You may have to change the indexes to be 0 based: 0-2 vs 1-3

[FrederikB]

Okay! I got it all working now!
So far so good, how will i now check for a winner?

Updated first post with updated sourcecode

[Norm]

if (row == 1) {
			row = 0;
		}

How about: row = row - 1

If you can read Javascript, here's one way to do it:
http://normsstuff.zxq.net/Games/TicTacToe.html#top

[FrederikB]

I have it working now with this code:

public boolean isWon(int token) {
		for (int i = 0; i < 3; i++)
			if ((gameBoard[i][0] == token) && (gameBoard[i][1] == token)
					&& (gameBoard[i][2] == token)) {
				return true;
			}
 
		for (int j = 0; j < 3; j++)
			if ((gameBoard[0][j] == token) && (gameBoard[1][j] == token)
					&& (gameBoard[2][j] == token)) {
				return true;
			}
 
		if ((gameBoard[0][0] == token) && (gameBoard[1][1] == token)
				&& (gameBoard[2][2] == token)) {
			return true;
		}
 
		if ((gameBoard[0][2] == token) && (gameBoard[1][1] == token)
				&& (gameBoard[2][0] == token)) {
			return true;
		}
 
		return false;
	}

Thanks for all the help!!

/solved