Thread: ConnectFour

We have to make a ConnectFour game in java for a project. I think I have managed to code most of it properly (Let me know if this is wrong). I''m having trouble figuering out how to decide who wins. I know you can win connect 4 horizontally, vertically, and diagonally( if the board size allows it).
Here's the link for reference: CMSC 202 - Spring 2013 - Project 2

Here's my ConnectFour.java class

package proj2;
 
public class ConnectFour 
{
	private String player1 = "";
	private String player2 = "";
	private int boardArea = 0;
	private int playerPieces = 0;
	private boolean turn = true;
	private int rows = 0;
	private int columns = 0;
	private int spot = 0;
	Move[][] board = new Move [rows][columns];
 
 
	public ConnectFour( int rows, int columns, String player1, String player2 )
	{
		this.rows = rows;
		this.columns = columns;
		this.player1 = player1;
		this.player2 = player2;
 
 
		for(int i = 0; i < rows; i++)
		{
			for( int j = 0;  j < columns ; j++)
			{
				board[i][j] = Move.EMPTY;
			}
		}
 
	}
 
	public int getBoardArea()
	{
		boardArea = rows * columns;
		return boardArea;
	}
 
	public void turn(int columns, boolean playerTurn)
	{//sorts through the column by rows. Starting at the top row.
 
		if(board[0][columns] != Move.EMPTY)
		{
			throw new RuntimeException("Columns is full. Try again.");
		}
 
		for(int i = 0; i < rows ; i++ )
		{
			if(board[i][columns] != Move.EMPTY)
			{
				spot = i;
			}
		}
 
	    if(playerTurn == true)//if it's player ones turn place piece 
	    						//on the board
		{
			board[spot][columns] = Move.PLAYER1;
		}
 
		else if(playerTurn == false)//if it's player twos turn place piece 
									//on the board
		{
			board[spot][columns] = Move.PLAYER2;
		}
 
	}
 
	public void setBoardArea()
	{
		//if(boardArea )
	}
 
	public void setPieces(int redPieces, int blackPieces )
	{
		//sets red and black pieces to players. P1 gets red P2 gets black.
		playerPieces = redPieces;
		playerPieces = blackPieces;
	}
 
	public void winCondition()//checks if a player has won
	{
 
	}
 
 
}

Here's my Enum Move

package proj2;
 
public enum Move {
	 PLAYER1, PLAYER2, EMPTY
}

Here's my Project2.java class

package proj2;
import java.util.Scanner;
public class Project2 {
 
	/** 
	 * This class drives the Connect Four game.
	 * @version 3/10/2013
	 * @author Nathan Graddick <grad1@umbc.edu>
	 * @project CMSC 202 - Spring 2013 - Project 2
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String selection = "";
		String player1 = "";
		String player2 = "";
		int rows = 0;
		int columns = 0;
	    boolean move = true;
 
 
 
		Scanner scan = new Scanner(System.in);
		System.out.println("Player1: Enter your name:");
		 player1 = scan.nextLine();
 
		System.out.println("Player2: Enter your name:");
		player2 = scan.nextLine();
 
		System.out.println("How many rows do you want?");
		rows = scan.nextInt();
 
		System.out.println("How many columns do you want?");
		columns = scan.nextInt();
 
		ConnectFour board = new ConnectFour(rows, columns, player1, player2);
		System.out.println("The area of the board is: " + board.getBoardArea());
 
		do
		{
			/*for(int i = 0; i < rows; i++)
			{
				board[i][i] = scan.nextLine();
				for(int j = 0; i < columns; i++)
				{
					board[j][j] = scan.nextLine();
				}
				System.out.println(columns);
			}
			System.out.println(rows);*/
 
 
 
		}while(!selection.equalsIgnoreCase("Q"));//exits the do while loop
	}
}

My fault. The users are prompt to input their names and then they are asked to input the size of the board that they want to play on. However, the board must have at least 25 spaces. So you can have a board of 4x7 (I don't know why you would want that) but if it was 4x4 it would not work.

A T.A pointed out that I have a problem with my for loop in my turn method in the ConnectFour Class. I keep getting an out of bounds error and he thinks that this may be the case as I have no way of exiting the for loop. I know I need to return a condition to exit it, but if I do I break my program. Also, for the life of me, I've no idea how to write the toString method so I can display the board. It has to look like the example in the link.

I get this error.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at proj2.ConnectFour.<init>(ConnectFour.java:27)
at proj2.Project2.main(Project2.java:36)

I know I need to fix it, but I'm not sure how. The compiler says the problem happens where I put a comment at. I'm unsure why it's wrong and how to fix it.

public ConnectFour( int rows, int columns, String player1, String player2 )
	{
		this.rows = rows;
		this.columns = columns;
		this.player1 = player1;
		this.player2 = player2;
 
		for(int i = 0; i < rows; i++)//Makes the entire board empty
		{
			for( int j = 0;  j < columns ; j++)
			{
				board[i][j] = Move.EMPTY;//problem happens here
			}
		}
 
	}

So, I think I fixed the problem. I copied that for loop and put it in a setter method. That fixed the out of bounds problem. As, of now I'm working on a toString method to display the state of the board. Thank you for you help.

Yes. I have also managed to get a toString method to print out the board. All I need to do now is figuring out how to do the win conditions and properly displaying the players pieces on the board.

So....I hit another snag. I'm trying to come up with conditions on wining in all 3 directions. I know I need a separate method for each, but what I have isn't working. I'm getting an out of bounds error again. I am at an absolute loss as to what do to.

package proj2;
 
public class ConnectFour 
{
	private String player1 = "";
	private String player2 = "";
	private int boardArea = 0;
	private String playerPieces = "";
	private boolean turn = true;
	private int rows = 0;
	private int columns = 0;
	private int spot = 0;
	private String dash = "-";
	private int MIN_BOARD = 25;
	Move[][] board;
 
 
 
 
	public ConnectFour( int rows, int columns, String player1, String player2)
	{
		this.rows = rows;
		this.columns = columns;
		this.player1 = player1;
		this.player2 = player2;
	}
 
	public int getBoardArea()
	{
		boardArea = rows * columns;
		return boardArea;
	}
 
	public void setBoard()
	{
		 board = new Move [rows][columns];
		for(int i = 0; i < rows; i++)//Makes the entire board empty
		{
			for( int j = 0;  j < columns ; j++)
			{
				board[i][j] = Move.EMPTY;
			}
		}
	}
 
	public int turn(int columns, boolean playerTurn)
	{
		//sorts through the column by rows. Starting at the bottom row.
		boolean spotFound;
		int win = 1;
 
		if(board[0][columns] != Move.EMPTY)
		{
			throw new RuntimeException("The column is full. Try again.");
		}
 
		spotFound = false;
		for(int i = board.length -1; i >= 0; i-- )
		{
			if(board[i][columns] == Move.EMPTY && spotFound == false)
			{
				spot = i;
				//creates a boolean flag to get out of the loop
				spotFound = true;
			}
		}
 
	    if(playerTurn == true)//if it's player one's turn place piece 
	    						//on the board
		{
			board[spot][columns] = Move.PLAYER1;
			//after you place the piece calls win method to see if they won
			win = winCondition(true);
		}
 
		else if(playerTurn == false)//if it's player two's turn place piece 
									//on the board
		{
			board[spot][columns] = Move.PLAYER2;
			//after you place the piece calls win method to see if they won
			win = winCondition(false);	
 
		}
	    if (win == 0)
	    {
	    	return 0;
 
	    }
	    else
	    	return 1;
 
 
	}
 
 
	public int winCondition(boolean playerTurn)//checks if a player has won
	{
		int win = 0;
		if(playerTurn == true)
		{
		  win = checkVertical(true);
		  if(win == 0)
		  {
			  System.out.println("You win!");
			  return 0;
		  }
		  else return 1;
		}
		else
		{
		  win = checkVertical(false);
			  if(win == 0)
			  {
				  System.out.println("You win!");
				  return 0;
			  }
			  else return 1;
 
		}
 
	}
 
	public int checkVertical(boolean playerTurn)
	{
		int count = 0;
 
		if(playerTurn == true)//checks to see if playerOne has won vertically
		{
			for(int i = 0; i < rows && board[columns][i] == Move.PLAYER1; i++)//this line is the problem
			{
				count++;
			}
			if(count > 3)
			{
				return 0;
			}
			else
			{
				return 1;
			}
		}
 
		else//checks to see if playerTwo has won vertically
		{
			for(int i = 0; i < rows && board[columns][i] == Move.PLAYER2; i++)
			{
				count++;
			}
			if(count > 3)
			{
				System.out.println("You win!");
				return 0;
			}
			else
			{
				return 1;
			}
		}
	}
 
	public int checkHorizontal(boolean playerTurn)
	{
		int count = 0;
 
		if(playerTurn == true)//checks to see if playerOne has won vertically
		{
			for(int i = 0; i < columns && board[rows][i] == Move.PLAYER1; i++)
			{
				count++;
			}
			if(count > 3)
			{
				System.out.println("You win!");
				return 0;
			}
			else
			{
				return 1;
			}
		}
 
		else//checks to see if playerTwo has won vertically
		{
			for(int i = 0; i < columns && board[rows][i] == Move.PLAYER2; i++)
			{
				count++;
			}
			if(count > 3)
			{
				System.out.println("You win!");
				return 0;
			}
			else
			{
				return 1;
			}
		}
	}
 
	/*public int checkDiagonally(boolean playerTurn)
	{
		int count = 0;
 
		if(playerTurn == true)//checks to see if playerOne has won vertically
		{
			for(int i = 0; i < columns && board[rows][i] == Move.PLAYER1; i++)
			{
				count++;
			}
			if(count > 3)
			{
				System.out.println("You win!");
				return 0;
			}
			else
			{
				return 1;
			}
		}
 
		else//checks to see if playerTwo has won vertically
		{
			for(int i = 0; i < columns && board[rows][i] == Move.PLAYER2; i++)
			{
				count++;
			}
			if(count > 3)
			{
				System.out.println("You win!");
				return 0;
			}
			else
			{
				return 1;
			}
		}
	}*/
 
	public String toString()
	{
		String str = "";
		for(int i = 0; i < rows; i ++)
		{
			for(int j = 0; j < columns; j++)
			{
				if(board[i][j] == Move.EMPTY)
				{
					str += dash;
				}
 
				if(board[i][j] == Move.PLAYER1)
				{
					str += "X";
				}
 
				if(board[i][j] == Move.PLAYER2)
				{
					str += "O";
				}
			}
			str += "\n";
		}
 
		return str;
	}	
}

This is the line that the compiler says is broken:

if(playerTurn == true)//checks to see if playerOne has won vertically
		{
			for(int i = 0; i < rows && board[columns][i] == Move.PLAYER1; i++)//this line is the problem
			{
				count++;
			}
			if(count > 3)
			{
				return 0;
			}
			else
			{
				return 1;
			}
		}

My apologies:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5
at proj2.ConnectFour.checkVertical(ConnectFour.java:1 59)
at proj2.ConnectFour.winCondition(ConnectFour.java:13 1)
at proj2.ConnectFour.turn(ConnectFour.java:99)
at proj2.Project2.main(Project2.java:57)