Data commit

Task/Tic-tac-toe/Scala/tic-tac-toe.scala

@@ -0,0 +1,82 @@
+package object tictactoe {
+  val Human = 'X'
+  val Computer = 'O'
+  val BaseBoard = ('1' to '9').toList
+  val WinnerLines = List((0,1,2), (3,4,5), (6,7,8), (0,3,6), (1,4,7), (2,5,8), (0,4,8), (2,4,6))
+  val randomGen = new util.Random(System.currentTimeMillis)
+}
+
+package tictactoe {
+
+class Board(aBoard : List[Char] = BaseBoard) {
+
+  def availableMoves = aBoard.filter(c => c != Human && c != Computer)
+
+  def availableMovesIdxs = for ((c,i) <- aBoard.zipWithIndex if c != Human && c != Computer) yield i
+
+  def computerPlays = new Board(aBoard.updated(availableMovesIdxs(randomGen.nextInt(availableMovesIdxs.length)), Computer))
+
+  def humanPlays(move : Char) = new Board(aBoard.updated(aBoard.indexOf(move), Human))
+
+  def isDraw = aBoard.forall(c => c == Human || c == Computer)
+
+  def isWinner(winner : Char) =
+    WinnerLines.exists{case (i,j,k) => aBoard(i) == winner && aBoard(j) == winner && aBoard(k) == winner}
+
+  def isOver = isWinner(Computer) || isWinner(Human) || isDraw
+
+  def print {
+    aBoard.grouped(3).foreach(row => println(row(0) + " " + row(1) + " " + row(2)))
+  }
+
+  def printOverMessage {
+    if (isWinner(Human)) println("You win.")
+    else if (isWinner(Computer)) println("Computer wins.")
+    else if (isDraw) println("It's a draw.")
+    else println("Not over yet, or something went wrong.")
+  }
+
+}
+
+
+object TicTacToe extends App {
+
+   def play(board : Board, turn : Char) {
+
+    // Reads a char from input until it is one of
+    // the available moves in the current board
+    def readValidMove() : Char = {
+      print("Choose a move: ")
+      val validMoves = board.availableMoves
+      val move = readChar
+      if (validMoves.contains(move)) {
+        move
+      } else {
+        println("Invalid move. Choose another one in " + validMoves)
+        readValidMove()
+      }
+    }
+
+
+    board.print
+
+    if (board.isOver) {
+      board.printOverMessage
+      return
+    }
+
+    if (turn == Human) { // Human plays
+      val nextBoard = board.humanPlays(readValidMove)
+      play(nextBoard, Computer)
+    } else { // Computer plays
+      println("Computer plays: ")
+      val nextBoard = board.computerPlays
+      play(nextBoard, Human)
+    }
+  }
+
+  play(new Board(),Human)
+
+}
+
+}