Please help me, My professor asked to have a line by line explanation of this code for tic tac toe.

/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package tictactoe.java;

import java.util.Scanner;

public class TicTacToeJava { public static Scanner sc = new Scanner(System.in); /** * @param args the command line arguments */ public static void main(String[] args) { final int SIZE = 3; char[][] board = new char[SIZE][SIZE]; // game board

resetBoard(board); // initialize the board (with ' ' for all cells)

// First, welcome message and display the board. System.out.println("===== WELCOME TO THE TIC-TAC-TOE GAME!! ===== "); showBoard(board);

// Then ask the user which symbol (x or o) he/she wants to play. System.out.print(" Which symbol do you want to play, \"x\" or \"o\"? "); char userSymbol = sc.next().toLowerCase().charAt(0); char compSymbol = (userSymbol == 'x') ? 'o' : 'x';

// Also ask whether or not the user wants to go first. System.out.println(); System.out.print(" Do you want to go first (y/n)? "); char ans = sc.next().toLowerCase().charAt(0);

int turn; // 0 -- the user, 1 -- the computer int remainCount = SIZE * SIZE; // empty cell count

// THE VERY FIRST MOVE. if (ans == 'y') { turn = 0; userPlay(board, userSymbol); // user puts his/her first tic } else { turn = 1; compPlay(board, compSymbol); // computer puts its first tic } // Show the board, and decrement the count of remaining cells. showBoard(board); remainCount--;

// Play the game until either one wins. boolean done = false; int winner = -1; // 0 -- the user, 1 -- the computer, -1 -- draw

while (!done && remainCount > 0) { // If there is a winner at this time, set the winner and the done flag to true. done = isGameWon(board, turn, userSymbol, compSymbol); // Did the turn won?

if (done) winner = turn; // the one who made the last move won the game else { // No winner yet. Find the next turn and play. turn = (turn + 1 ) % 2;

if (turn == 0) userPlay(board, userSymbol); else compPlay(board, compSymbol);

// Show the board after one tic, and decrement the rem count. showBoard(board); remainCount--; } }

// Winner is found. Declare the winner. if (winner == 0) System.out.println(" ** YOU WON. CONGRATULATIONS!! **"); else if (winner == 1) System.out.println(" ** YOU LOST.. Maybe next time :) **"); else System.out.println(" ** DRAW... **");

}

public static void resetBoard(char[][] brd) { for (int i = 0; i < brd.length; i++) for (int j = 0; j < brd[0].length; j++) brd[i][j] = ' '; }

public static void showBoard(char[][] brd) { int numRow = brd.length; int numCol = brd[0].length;

System.out.println();

// First write the column header System.out.print(" "); for (int i = 0; i < numCol; i++) System.out.print(i + " "); System.out.print(' ');

System.out.println(); // blank line after the header

// The write the table for (int i = 0; i < numRow; i++) { System.out.print(i + " "); for (int j = 0; j < numCol; j++) { if (j != 0) System.out.print("|"); System.out.print(" " + brd[i][j] + " "); }

System.out.println();

if (i != (numRow - 1)) { // separator line System.out.print(" "); for (int j = 0; j < numCol; j++) { if (j != 0) System.out.print("+"); System.out.print("---"); } System.out.println(); } } System.out.println(); }

public static void userPlay(char[][] brd, char usym) { System.out.print(" Enter the row and column indices: "); int rowIndex = sc.nextInt(); int colIndex = sc.nextInt();

while (brd[rowIndex][colIndex] != ' ') { System.out.print(" !! The cell is already taken. Enter the row and column indices: "); rowIndex = sc.nextInt(); colIndex = sc.nextInt(); }

brd[rowIndex][colIndex] = usym; }

public static void compPlay(char[][] brd, char csym) { // Find the first empty cell and put a tic there. for (int i = 0; i < brd.length; i++) { for (int j = 0; j < brd[0].length; j++) { if (brd[i][j] == ' ') { // empty cell brd[i][j] = csym; return; } } } }

public static boolean isGameWon(char[][] brd, int turn, char usym, char csym) { char sym; if (turn == 0) sym = usym; else sym = csym;

int i, j; boolean win = false;

// Check win by a row for (i = 0; i < brd.length && !win; i++) { for (j = 0; j < brd[0].length; j++) { if (brd[i][j] != sym) break; } if (j == brd[0].length) win = true; }

// Check win by a column for (j = 0; j < brd[0].length && !win; j++) { for (i = 0; i < brd.length; i++) { if (brd[i][j] != sym) break; } if (i == brd.length) win = true; }

// Check win by a diagonal (1) if (!win) { for (i = 0; i < brd.length; i++) { if (brd[i][i] != sym) break; } if (i == brd.length) win = true; }

// Check win by a diagonal (2) if (!win) { for (i = 0; i < brd.length; i++) { if (brd[i][brd.length - 1 - i] != sym) break; } if (i == brd.length) win = true; }

// Finally return win return win; } }