Tictactoe game

**Fowler** · 10-31-2010, 04:49 PM

Hello

I am currently making a tictactoe game for two players. So far I have made the gameboard work, so both players can write the name before they make their X or O which shows up on the board afterwards.

My problem now, is to make it so it isn't possible to make a move where there already is an X or O.

So far, this is what I have made:

Java Code:

/*
Date: 2010.10.29
*/

import java.io.*;     // for File
import java.util.*;

public class tictactoe

{
	public static char[][] gameboard = new char[3][3]; 
	public static Scanner keyboard = new Scanner(System.in);
	public static String[] player = {"dummy","dummy"};
	
	public static void main(String[] args)
	{

		Arrays.fill(gameboard[0], ' ');
		Arrays.fill(gameboard[1], ' ');
		Arrays.fill(gameboard[2], ' ');
		
		System.out.println("\nWelcome to the game Tic Tac Toe");	
		System.out.print("Hello, what's the name of player no 1 ? ");	
		player[0] = keyboard.next();
		System.out.print("Hello, what's the name of player no ? ");	
		player[1] = keyboard.next();

		drawgameboard();
		int player = 0;
		boolean finished = false;
		while(!finished)
		{
			move(player);
			drawgameboard();
			player = (player + 1) % 2;
		}
		
	}	

	
	public static void move(int playerno)
	{
		int col = 99, row = 99;
		while ((col == 99) || (row == 99))
		{
			System.out.print("\nHello " + player[playernr] + " make your move. (column-letter and row-number): ");	
			String x = keyboard.next();
			String y = keyboard.next();
			if (x.equalsIgnoreCase("A")) col = 0;
			if (x.equalsIgnoreCase("B")) col = 1;
			if (x.equalsIgnoreCase("C")) col = 2;
			if (y.equals("1")) row = 0;
			if (y.equals("2")) row = 1;
			if (y.equals("3")) row = 2;
		}
		char draw = 'O';
		if (playernr == 0) draw = 'X';
		gameboard[row][col] = draw;
	}
	
	public static void drawgameboard()
	{
	
		System.out.println();
		System.out.println();
		System.out.println("     A   B   C  ");
		System.out.println("   +---+---+---+");
		System.out.printf(" 1 | %c | %c | %c |\n",gameboard[0][0],gameboard[0][1],gameboard[0][2]);
		System.out.println("   +---+---+---+");
		System.out.printf(" 2 | %c | %c | %c |\n",gameboard[1][0],gameboard[1][1],gameboard[1][2]);
		System.out.println("   +---+---+---+");
		System.out.printf(" 3 | %c | %c | %c |\n",gameboard[2][0],gameboard[2][1],gameboard[2][2]);
		System.out.println("   +---+---+---+");
		
	}
	
}

**Fowler** · 10-31-2010, 04:53 PM

Sorry it seems a little mixed up. This is my first post, and I didn't knew how to attach the code, so it would be more clear to look at.

**Fubarable** · 10-31-2010, 04:55 PM

Originally Posted by Fowler

Sorry it seems a little mixed up. This is my first post, and I didn't knew how to attach the code, so it would be more clear to look at.

Edit the first post to add code tags. Place the tag

[code]

above your block of code, and the tag:

[/code]

below your block of code. Luck!

**Fowler** · 10-31-2010, 05:05 PM

That helped, thanks Fubarable

**Fubarable** · 10-31-2010, 05:37 PM

Originally Posted by Fowler

My problem now, is to make it so it isn't possible to make a move where there already is an X or O.

Check your gameboard[row][col] before committing a move. If it already contains a non-space character, then re-ask for input until correct input has been given. You will need to use a while loop to do this.

**berkeleybross** · 10-31-2010, 05:50 PM

Im confused.
Are you making tic tac toe, or battleships?

Also, there is a much better way of making those game boards.
For instance:

Java Code:

// spiller 1
System.out.println ();
System.out.println("     A   B   C   D   E   F   G   H   I   J  ");
System.out.println("   +---+---+---+---+---+---+---+---+---+---+");
for (int row = 0; row < 10; row++) {
    if (row == 9) {
        System.out.print (" " + (row + 1) + "|");
    } else {
        System.out.print (" " + (row + 1) + " |");
    }

    for (int col = 0; col < 10; col++) {
        System.out.print (" " + gameboard[row][col] + " |");
    }
    System.out.println ("");
    System.out.println("   +---+---+---+---+---+---+---+---+---+---+");
}

The advantage of doing it this way is that less code is required, and it is more extensible.
i.e. if i wanted a game board a 100 squares by a hundred, then all i would need to do is increase "row < 10" and "col < 10" to "row < 100" and "col < 100".

If you dont understand the code, please ask.

Onto your actual question.
To stop someone from putting a piece into a filled square, then all you have to do is check the contents of the square.
Some pseudocode -

Java Code:

boolean validsquare = false;
while (!validsquare) {
    ask user for square
    if square == empty {
        place piece in square
        validsquare = true;
    } else {
        tell user invalid location
    }
}

in your case, checking if the square is empty will be checking if it contains a space character

Hope this helps!

**Fowler** · 10-31-2010, 06:56 PM

Originally Posted by berkeleybross

Im confused.
Are you making tic tac toe, or battleships?

Also, there is a much better way of making those game boards.
For instance:

Java Code:

// spiller 1
System.out.println ();
System.out.println("     A   B   C   D   E   F   G   H   I   J  ");
System.out.println("   +---+---+---+---+---+---+---+---+---+---+");
for (int row = 0; row < 10; row++) {
    if (row == 9) {
        System.out.print (" " + (row + 1) + "|");
    } else {
        System.out.print (" " + (row + 1) + " |");
    }

    for (int col = 0; col < 10; col++) {
        System.out.print (" " + gameboard[row][col] + " |");
    }
    System.out.println ("");
    System.out.println("   +---+---+---+---+---+---+---+---+---+---+");
}

The advantage of doing it this way is that less code is required, and it is more extensible.
i.e. if i wanted a game board a 100 squares by a hundred, then all i would need to do is increase "row < 10" and "col < 10" to "row < 100" and "col < 100".

If you dont understand the code, please ask.

Onto your actual question.
To stop someone from putting a piece into a filled square, then all you have to do is check the contents of the square.
Some pseudocode -

Java Code:

boolean validsquare = false;
while (!validsquare) {
    ask user for square
    if square == empty {
        place piece in square
        validsquare = true;
    } else {
        tell user invalid location
    }
}

in your case, checking if the square is empty will be checking if it contains a space character

Hope this helps!

Sorry, it seems like I got it mixed up with the upload of the code. I have changed it with my tictactoe-game, instead of the battleship game I am also working on.

As I understand it, I have to make it so that the code you wrote has to be connected somehow to where the c% is in the board. I have tried to do it in some different ways, I just don't seem to see how to handle this one. I would be very thankful if you could help me with this one.

**Fubarable** · 10-31-2010, 07:04 PM

Have you read my other recommendation above?

**berkeleybross** · 10-31-2010, 07:56 PM

you need to change the method public static void move(int playerno)
Before you actually make the move (gameboard[row][col] = draw;) you need to check if that position is empty.
You can insert my pseudo code around the parsing and validation of the input.

**Fowler** · 10-31-2010, 10:29 PM

I don't know if I have understood it terribly wrong, but this is how I have inserted your suggestion in my code:

Java Code:

import java.io.*;     // for File
import java.util.*;

public class z

{
	public static char[][] gameboard = new char[3][3]; 
	public static Scanner keyboard = new Scanner(System.in);
	public static String[] player = {"dummy","dummy"};
	
	public static void main(String[] args)
	{

		Arrays.fill(gameboard[0], ' ');
		Arrays.fill(gameboard[1], ' ');
		Arrays.fill(gameboard[2], ' ');
		
		System.out.println("\nWelcome to the game Tic Tac Toe");	
		System.out.print("Hello, what's the name of player no 1 ? ");	
		player[0] = keyboard.next();
		System.out.print("Hello, what's the name of player no ? ");	
		player[1] = keyboard.next();

		drawgameboard();
		int player = 0;
		boolean finished = false;
		while(!finished)
		{
			move(player);
			drawgameboard();
			player = (player + 1) % 2;
		}
		
	}	

	
	public static void move(int playerno)
	{
		int col = 99, row = 99;
		while ((col == 99) || (row == 99))
		
		boolean validsquare = false;
		while (!validsquare) 

	{
			//ask user for square
			System.out.print("\nHello " + player[playerno] + " make your move. (column-letter and row-number): ");	
			String x = keyboard.next();
			String y = keyboard.next();		
			if x,y == empty 
			{
				if (x.equalsIgnoreCase("A")) col = 0;
				if (x.equalsIgnoreCase("B")) col = 1;
				if (x.equalsIgnoreCase("C")) col = 2;
				if (y.equals("1")) row = 0;
				if (y.equals("2")) row = 1;
				if (y.equals("3")) row = 2;
				validsquare = true;
			} 
    
    		else 
	    	{
    	    	System.out.println("Position taken - please try again!");
	    	}	
	}
		char draw = 'O';
		if (playerno == 0) draw = 'X';
		gameboard[row][col] = draw;
	}
	
		
	
	public static void drawgameboard()
	{
	
		System.out.println();
		System.out.println();
		System.out.println("     A   B   C  ");
		System.out.println("   +---+---+---+");
		System.out.printf(" 1 | %c | %c | %c |\n",gameboard[0][0],gameboard[0][1],gameboard[0][2]);
		System.out.println("   +---+---+---+");
		System.out.printf(" 2 | %c | %c | %c |\n",gameboard[1][0],gameboard[1][1],gameboard[1][2]);
		System.out.println("   +---+---+---+");
		System.out.printf(" 3 | %c | %c | %c |\n",gameboard[2][0],gameboard[2][1],gameboard[2][2]);
		System.out.println("   +---+---+---+");
		
	}
	
}

**Fowler** · 10-31-2010, 10:38 PM

Originally Posted by Fubarable

Have you read my other recommendation above?

Sorry, I didn't notice it before now. I have tried what you suggested, but it don't give so much sense to me. I am pretty new to this, so I kind of have to get it as specific as possible to know what people mean when I get help :S

**berkeleybross** · 10-31-2010, 10:55 PM

I really shouldnt do this, but here is what i was thinking:

Java Code:

public static void move(int playerno) {
    System.out.print("\nHello " + player[playernr] + " make your move. (column-letter and row-number): ");
    boolean validMove = false;
    int row = -1;
    int col = -1;
    while (!validMove) {
        // get input
        String x = keyboard.next();
        String y = keyboard.next();

        // parse input
        if (x.equalsIgnoreCase("A")) col = 0;
        if (x.equalsIgnoreCase("B")) col = 1;
        if (x.equalsIgnoreCase("C")) col = 2;
        if (y.equals("1")) row = 0;
        if (y.equals("2")) row = 1;
        if (y.equals("3")) row = 2;

        // check if valid location
        if (row != -1) {
            if (col != -1) {
                // check if square is empty
                if (gameboard[row][col] == ' ') {
                    validmove = true;
                } else {
                    System.out.println ("invalid move, try again.");
                }
            } else {
                System.out.println ("Invalid location: Col must be 'A', 'B' or 'C'. Try again.");
            }
        } else {
            System.out.println ("Invalid location: Row must be '1', '2' or '3'. Try again.");
        }
    }

    char draw = 'O';
    if (playernr == 0) draw = 'X';
    gameboard[row][col] = draw;
}

If you dont understand the code, please ask.