Simple TicTacToe demo using if blocks for El Camino High School

TicTacToe.java

import java.util.Scanner;

public class TicTacToe {
  public static char X = 'X';
  public static char O = 'O';
  public static char B = ' ';

  public static void main(String[] args) {
    /*
     * Squares are associated with following variables.
     *  	 	1	 	2	 	3
     * 1	|	a	|	b	|	c	|
     * 2	|	d	|	e	|	f	|
     * 3	|	g	|	h	|	i	|
     */
    // Initialize squares to blank.

    char a = B, b = B, c = B, d = B, e = B, f = B, g = B, h = B, i = B;

    Scanner input = new Scanner(System.in);

    System.out.println("Welcome to Tic-tac-toe");

    // Get player's names.
    System.out.print("Enter player 1's name? ");
    String player1 = input.nextLine();
    System.out.print("Enter player 2's name? ");
    String player2 = input.nextLine();

    // Print blank board.
    printBoard(a, b, c, d, e, f, g, h, i);

    for (int move = 0; move < 9; move++) {
      char turn;

      // Check whose turn it is...
      if (move % 2 == 0) {
        System.out.println("It is " + player1 + "'s turn...");
        turn = X;
      } else {
        System.out.println("It is " + player2 + "'s turn...");
        turn = O;
      }

      // Choose a square.
      System.out.print("Pick a row number: ");
      int row = input.nextInt();
      System.out.print("Pick a column number: ");
      int column = input.nextInt();

      // Based on whose turn it is and the picked square, fill in either an X or an O.
      if (row == 1 && column == 1 && a == B) {
        a = turn;
      } else if (row == 1 && column == 2 && b == B) {
        b = turn;
      } else if (row == 1 && column == 3 && c == B) {
        c = turn;
      } else if (row == 2 && column == 1 && d == B) {
        d = turn;
      } else if (row == 2 && column == 2 && e == B) {
        e = turn;
      } else if (row == 2 && column == 3 && f == B) {
        f = turn;
      } else if (row == 3 && column == 1 && g == B) {
        g = turn;
      } else if (row == 3 && column == 2 && h == B) {
        h = turn;
      } else if (row == 3 && column == 3 && i == B) {
        i = turn;
      } else {
        System.out.println("You entered incorrect input! Try again...");
        move--;
      }

      // Print board.
      printBoard(a, b, c, d, e, f, g, h, i);

      // Check if there is a winner.
      checkWinner(a, b, c, d, e, f, g, h, i, player1, player2);
    }

    // We played all 9 moves and no one has won!
    System.out.println("Stalemate!");
  }


  public static void checkWinner(
      char a,
      char b,
      char c,
      char d,
      char e,
      char f,
      char g,
      char h,
      char i,
      String player1,
      String player2
  ) {
    // Either X or O.
    char winnerType;

    if (a == b && b == c) {
      // First row.
      winnerType = a;
    } else if (d == e && e == f) {
      // Second row.
      winnerType = d;
    } else if (g == h && h == i) {
      // Third row.
      winnerType = g;
    } else if (a == d && d == g) {
      // First column.
      winnerType = a;
    } else if (b == e && e == h) {
      // Second column.
      winnerType = b;
    } else if (c == f && f == i) {
      // Third column.
      winnerType = c;
    } else if (a == e && b == i) {
      // First diagonal.
      winnerType = a;
    } else if (g == e && e == c) {
      // Second diagonal.
      winnerType = g;
    } else {
      return;
    }

    // Check if someone won and end the game.
    if (winnerType == X) {
      System.out.println(player1 + " won the game!!!");
      System.exit(0);
    } else if (winnerType == O) {
      System.out.println(player2 + " won the game!!!");
      System.exit(0);
    }
  }

  public static void printBoard(
      char a,
      char b,
      char c,
      char d,
      char e,
      char f,
      char g,
      char h,
      char i
  ) {
    // Print the board in a tabular form.
    System.out.println();
    System.out.println(" \t \t1\t \t2\t \t3");
    System.out.println("1\t|\t" + a + "\t|\t" + b + "\t|\t" + c + "\t|\t");
    System.out.println("2\t|\t" + d + "\t|\t" + e + "\t|\t" + f + "\t|\t");
    System.out.println("3\t|\t" + g + "\t|\t" + h + "\t|\t" + i + "\t|\t");
    System.out.println();
  }
}