Merge pull request #270 from mtwn105/tic-tac-toe

Added program for tic tac toe game

Author: SarthakKeshari

Coding Application(Games and more)/TicTacToe.java

@@ -0,0 +1,254 @@
+package dev.amitwani;
+
+/*
+ *
+ * A program for end user so that he/she can play tic-tac-toe game with computer
+ * or game can be played by two end users.
+ *
+ * AUTHOR: Amit Wani (@mtwn105)
+ *
+ */
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+import java.util.Scanner;
+
+public class TicTacToe {
+
+    public static void main(String[] args) {
+
+        System.out.print("!!Welcome to Tic-Tac-Toe!!\n" +
+                "Decide your opponent:\n" +
+                "1) Play with computer\n" +
+                "2) Play with a friend\n" +
+                "Enter your choice –");
+
+        Scanner scanner = new Scanner(System.in);
+        int choice = scanner.nextInt();
+
+        scanner.nextLine();
+
+        // Game Board
+        String[] game = new String[]{"*", "*", "*", "*", "*", "*", "*", "*", "*"};
+
+        // Player Marks
+        String player1Mark = "X";
+        String player2Mark = "O";
+
+        // Flag for checking if game is over
+        boolean isGameOver = false;
+        int nextTurn = 0;
+
+        // If Playing vs Bot
+        if (choice == 1) {
+
+            // Get Player Name
+            System.out.print("\nEnter your name –");
+            String playerName = scanner.nextLine();
+
+            String computerName = "T-Bot";
+
+            System.out.println("Hey " + playerName + ", I am Computer. My name is ‘" + computerName + "’.");
+
+            System.out.print("\nWho’ll go first?\n" +
+                    "1) T-Bot\n" +
+                    "2) Me\n" +
+                    "Enter your choice –");
+
+            nextTurn = scanner.nextInt();
+
+            // Printing Initial Game Board
+            printGameBoard(game);
+
+            // Playing until game is over
+            while (!isGameOver) {
+
+                // Get Empty spaces remaining on the game board
+                List<Integer> emptySpaces = findEmptySpaces(game);
+
+                // If no empty spaces remaining & no winner is decided then its a draw
+                if (emptySpaces.size() == 0) {
+                    // DRAW
+                    System.out.println("RESULTS TIME: GAME IS A DRAW !!");
+                    break;
+                }
+
+                if (nextTurn == 1) {
+
+                    System.out.print("T-Bot’s turn: ");
+
+                    // For Bot, Picking random empty space
+                    Random random = new Random();
+                    int nextMove = emptySpaces.get(random.nextInt(emptySpaces.size()));
+
+                    System.out.print(nextMove);
+
+                    // Update the game board with bot's move
+                    updateGameBoard(game, nextMove, player1Mark);
+
+                    nextTurn = 2;
+                } else {
+
+                    System.out.print(playerName + "’s turn: ");
+
+                    // Get Player's Next Move
+                    playerNextMove(scanner, game, player2Mark, playerName, emptySpaces);
+
+                    nextTurn = 1;
+                }
+
+                // Print board after every move
+                printGameBoard(game);
+
+                // Check Result
+                isGameOver = checkResult(game, player1Mark, computerName, playerName);
+
+            }
+
+        } else if (choice == 2) {
+
+            // Get Player Details
+            System.out.print("\nEnter your name of player 1 –");
+            String player1Name = scanner.nextLine();
+            System.out.print("\nEnter your name of player 2 –");
+            String player2Name = scanner.nextLine();
+
+            System.out.print("\nWho’ll go first?\n" +
+                    "1) " + player1Name + "\n" +
+                    "2) " + player2Name + "\n" +
+                    "Enter your choice –");
+
+            nextTurn = scanner.nextInt();
+
+            // Printing Initial Game Board
+            printGameBoard(game);
+
+            // Playing until game is over
+            while (!isGameOver) {
+
+                // Get Empty spaces remaining on the game board
+                List<Integer> emptySpaces = findEmptySpaces(game);
+
+                // If no empty spaces remaining & no winner is decided then its a draw
+                if (emptySpaces.size() == 0) {
+                    // DRAW
+                    System.out.println("RESULTS TIME: GAME IS A DRAW !!");
+                    break;
+                }
+
+                if (nextTurn == 1) {
+
+                    System.out.print(player1Name + "’s turn: ");
+
+                    // Get Player's Next Move
+                    playerNextMove(scanner, game, player1Mark, player1Name, emptySpaces);
+
+                    nextTurn = 2;
+                } else {
+
+                    System.out.print(player2Name + "’s turn: ");
+
+                    // Get Player's Next Move
+                    playerNextMove(scanner, game, player2Mark, player2Name, emptySpaces);
+
+                    nextTurn = 1;
+                }
+
+                // Print board after every move
+                printGameBoard(game);
+
+                // Check Result
+                isGameOver = checkResult(game, player1Mark, player1Name, player2Name);
+
+            }
+
+        }
+
+    }
+
+    private static boolean checkResult(String[] game, String playerMark, String player1Name, String player2Name) {
+        // Check if game is over after every move
+        String result = checkIfGameOver(game);
+
+        boolean isGameOver = false;
+
+        if (result != null) {
+            isGameOver = true;
+            String winner = result.equals(playerMark) ? player1Name : player2Name;
+            System.out.println("RESULTS TIME:\n" + winner + " WON !!");
+        }
+        return isGameOver;
+    }
+
+    private static void playerNextMove(Scanner scanner, String[] game, String playerMark, String playerName, List<Integer> emptySpaces) {
+        int nextMove = scanner.nextInt();
+        boolean available = isSpaceEmpty(emptySpaces, nextMove);
+        while (!available) {
+            System.out.println("Invalid input. Space already filled.");
+            System.out.print(playerName + "’s turn: ");
+
+            nextMove = scanner.nextInt();
+            available = isSpaceEmpty(emptySpaces, nextMove);
+        }
+
+        updateGameBoard(game, nextMove, playerMark);
+    }
+
+    private static boolean isSpaceEmpty(List<Integer> emptySpaces, int nextMove) {
+        return emptySpaces.stream().anyMatch(x -> x == nextMove);
+    }
+
+    private static String checkIfGameOver(String[] game) {
+
+        // check columns
+        for (int i = 0; i < 3; i++) {
+            if (game[i].equals(game[i + 3]) && game[i + 3].equals(game[i + 6]) && !game[i].equals("*")) {
+                return game[i];
+            }
+        }
+
+        // check rows
+        for (int i = 0; i < 7; i += 3) {
+            if (game[i].equals(game[i + 1]) && game[i + 1].equals(game[i + 2]) && !game[i].equals("*")) {
+                return game[i];
+            }
+        }
+
+        // check diagonal
+        if (game[0].equals(game[4]) && game[4].equals(game[8]) && !game[0].equals("*")) {
+            return game[0];
+        }
+        if (game[2].equals(game[4]) && game[4].equals(game[6]) && !game[2].equals("*")) {
+            return game[2];
+        }
+
+        return null;
+    }
+
+    private static void updateGameBoard(String[] game, int nextMove, String playerMark) {
+        game[nextMove - 1] = playerMark;
+    }
+
+    private static List<Integer> findEmptySpaces(String[] game) {
+
+        List<Integer> emptySpaces = new ArrayList<>();
+
+        for (int i = 1; i <= game.length; i++) {
+            if (game[i - 1].equals("*")) {
+                emptySpaces.add(i);
+            }
+        }
+
+        return emptySpaces;
+    }
+
+    private static void printGameBoard(String[] game) {
+        System.out.println();
+        for (int i = 1; i < 10; i++) {
+            System.out.print(game[i - 1] + "\t");
+            if (i % 3 == 0)
+                System.out.println();
+        }
+    }
+}