import java.util.*;
public class GFG {
static String[] board;
static String turn;
// CheckWinner method will
// decide the combination
// of three box given below.
static String checkWinner()
{
for (int a = 0; a < 8; a++) {
String line = null;
switch (a) {
case 0:
line = board[0] + board[1] + board[2];
break;
case 1:
line = board[3] + board[4] + board[5];
break;
case 2:
line = board[6] + board[7] + board[8];
break;
case 3:
line = board[0] + board[3] + board[6];
break;
case 4:
line = board[1] + board[4] + board[7];
break;
case 5:
line = board[2] + board[5] + board[8];
break;
case 6:
line = board[0] + board[4] + board[8];
break;
case 7:
line = board[2] + board[4] + board[6];
break;
}
//For X winner
if (line.equals("XXX")) {
return "X";
}
// For O winner
else if (line.equals("OOO")) {
return "O";
}
}
for (int a = 0; a < 9; a++) {
if (Arrays.asList(board).contains(
String.valueOf(a + 1))) {
break;
}
else if (a == 8) {
return "draw";
}
}
// To enter the X Or O at the exact place on board.
System.out.println(
turn + "'s turn; enter a slot number to place "
+ turn + " in:");
return null;
}
// To print out the board.
/* |---|---|---|
| 1 | 2 | 3 |
|-----------|
| 4 | 5 | 6 |
|-----------|
| 7 | 8 | 9 |
|---|---|---|*/
static void printBoard()
{
System.out.println("|---|---|---|");
System.out.println("| " + board[0] + " | "
+ board[1] + " | " + board[2]
+ " |");
System.out.println("|-----------|");
System.out.println("| " + board[3] + " | "
+ board[4] + " | " + board[5]
+ " |");
System.out.println("|-----------|");
System.out.println("| " + board[6] + " | "
+ board[7] + " | " + board[8]
+ " |");
System.out.println("|---|---|---|");
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
board = new String[9];
turn = "X";
String winner = null;
for (int a = 0; a < 9; a++) {
board[a] = String.valueOf(a + 1);
}
System.out.println("Welcome to 3x3 Tic Tac Toe.");
printBoard();
System.out.println(
"X will play first. Enter a slot number to place X in:");
while (winner == null) {
int numInput;
// Exception handling.
// numInput will take input from user like from 1 to 9.
// If it is not in range from 1 to 9.
// then it will show you an error "Invalid input."
try {
numInput = in.nextInt();
if (!(numInput > 0 && numInput <= 9)) {
System.out.println(
"Invalid input; re-enter slot number:");
continue;
}
}
catch (InputMismatchException e) {
System.out.println(
"Invalid input; re-enter slot number:");
continue;
}
// This game has two player x and O.
// Here is the logic to decide the turn.
if (board[numInput - 1].equals(
String.valueOf(numInput))) {
board[numInput - 1] = turn;
if (turn.equals("X")) {
turn = "O";
}
else {
turn = "X";
}
printBoard();
winner = checkWinner();
}
else {
System.out.println(
"Slot already taken; re-enter slot number:");
}
}
// If no one win or lose from both player x and O.
// then here is the logic to print "draw".
if (winner.equalsIgnoreCase("draw")) {
System.out.println(
"It's a draw! Thanks for playing.");
}
// For winner -to display Congratulations! message.
else {
System.out.println(
"Congratulations! " + winner
+ "'s have won! Thanks for playing.");
}
}
}