I am trying to make a Tic-tac-toe game where the user gets to select whether they would like to play a single player game or a two player game. I have gotten both of them to work but am trying to make the AI have some logic as to where it places its "o". Currently, the computer randomly generates a row and a column and if the corresponding square in the array has a "-" (signifying that it is empty), it will fill it with an "o". I am looking for a simple way to go through the 2d array and sees if it has a way to win. If not, it should check if the user can win and prevent them from winning. If none of them are true, then it should randomly select a square and make it's move. Also, I am relatively new to Java so if I am doing something wrong, please let me know how to do it so that I can fix it and improve my own skills. Here is the code.
Driver File:
public class DriverTicTacToe
{
public static void main(String[] args)
{
TicTacToe game = new TicTacToe(); //creates an object
game.play();//this simulates the whole game from asking the number of players all the way to printing the win message.
}
}
Resource File:
import java.util.Scanner;
public class TicTacToe
{
//declares the symbol character that will hold either "x" or "o"
char symbol;
//create a 3*3 array of characters that acts as the board in the game.
char[][] board = new char[3][3];
//declares multiple integers used throughout the game simulation
int player = 1, row, col, numPlayers;
//creates scanner object used to get user input
Scanner kb = new Scanner(System.in);
//constructor that fill the board array with dashes.
public TicTacToe()
{
for(int i = 0; i <3; i++)
{
for(int j = 0; j < 3; j++)
board[i][j] = '-';
}
}
//asks the user for the number of players
public int getNumPlayers()
{
System.out.println("How many players are there (1 or 2)");
numPlayers = kb.nextInt();
return numPlayers;
}
//used to cycle through "x" and "o"
public void setSymbol(int playerNumber)
{
if (playerNumber % 2 == 1)
symbol = 'x';
else
symbol = 'o';
}
//prints the array as a 3*3 board
public void printBoard()
{
for(int i = 0; i < 3; i++)
{
for(int j = 0; j<3; j++)
System.out.print(board[i][j]);
System.out.println();
}
}
//checks if there is an empty place on the board
public boolean boardNotFilled()
{
for(int i = 0; i < 3; i++)
{
for(int j = 0; j < 3; j++)
{
if(board[i][j] == '-')
return true;
}
}
return false;
}
//checks if someone has won the game
public boolean checkGameOn()
{
if(board[0][0] == board[0][1] && board[0][1] == board[0][2] && board[0][0] != '-')
return false;
else if(board[1][0] == board[1][1] && board[1][1] == board[1][2] && board[1][0] != '-')
return false;
else if(board[2][0] == board[2][1] && board[2][1] == board[2][2] && board[2][0] != '-')
return false;
else if(board[0][0] == board[1][0] && board[1][0] == board[2][0] && board[0][0] != '-')
return false;
else if(board[0][1] == board[1][1] && board[1][1] == board[2][1] && board[0][1] != '-')
return false;
else if(board[0][2] == board[1][2] && board[1][2] == board[2][2] && board[0][2] != '-')
return false;
else if(board[0][0] == board[1][1] && board[1][1] == board[2][2] && board[0][0] != '-')
return false;
else if(board[0][2] == board[1][1] && board[1][1] == board[2][0] && board[0][2] != '-')
return false;
else
return true;
}
//ask user for a row. The number is decreased by one to get to the corresponding index
public void getRow()
{
System.out.println("Enter a row: ");
row = kb.nextInt() - 1;
//return row;
}
//ask user for a column. The number is decreased by one to get to the corresponding index
public void getColumn()
{
System.out.println("Enter a column: ");
col = kb.nextInt() - 1;
//return col;
}
//switches the value at a point from a "-" to the symbol
public boolean switchVal()
{
board[row][col] = symbol;
}
//selects to random numbers for a computer move. Keeps running until an empty index is found.
public void compMove()
{
while(true)
{
row = (int)(Math.random()*3);
col = (int)(Math.random()*3);
if(board[row][col] == '-')
break;
}
}
//Prints winner for a 2 player game
public void winStatement()
{
if(symbol == 'x')
System.out.println("Congratulations Player 1, you win");
else
System.out.println("Congratulations Player 2, you win");
}
//simulates a single player game
public void singlePlayer()
{
int playerNum = 1;
TicTacToe game = new TicTacToe();
while (game.checkGameOn() && game.boardNotFilled())
{
game.printBoard();
if(playerNum != 1)
{
System.out.println();
System.out.println("I made my move! Your turn.");
System.out.println();
}
game.setSymbol(playerNum);
game.getRow();
game.getColumn();
game.switchVal();
game.printBoard();
System.out.println();
System.out.println("Computer's turn!");
System.out.println();
playerNum++;
game.setSymbol(playerNum);
game.compMove();
game.switchVal();
playerNum++;
}
game.printBoard();
if(game.boardNotFilled())
System.out.println("Congratulations, you win!");
else
System.out.println("Game Tied");
}
//simulates a two player game
public void twoPlayer()
{
int playerNum = 1;
TicTacToe game = new TicTacToe();
while (game.checkGameOn() && game.boardNotFilled())
{
game.printBoard();
game.setSymbol(playerNum);
game.getRow();
game.getColumn();
game.switchVal();
playerNum++;
}
game.printBoard();
if(game.boardNotFilled())
game.winStatement();
else
System.out.println("Game Tied");
}
//simulates everything from asking user how many players all the way to running the game.
public void play()
{
TicTacToe game = new TicTacToe();
int numPlayers = game.getNumPlayers();
if(numPlayers == 1)
game.singlePlayer();
else if(numPlayers == 2)
game.twoPlayer();
else
System.out.println("Error");
}
}
