Tic-tac-toe.js

Tic-tac-toe.js

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+let board = [
+    ['', '', ''],       //3 x 3 board.
+    ['', '', ''],
+    ['', '', '']
+  ];
+
+  let w; // = width / 3;
+  let h; // = height / 3;
+
+  let computer = 'X'; //when the screen represents X that means computer player has make a move
+  let human = 'O'; ///when the screen represents O that means human has make a move
+  let currentPlayer = human;
+
+  function setup() {
+    createCanvas(400, 400); //canvas used to present graphics
+    w = width / 3;
+    h = height / 3;
+    bestMove();
+  }
+
+  function equals3(a, b, c) {
+    return a == b && b == c && a != '';
+  }
+
+  function checkWinner() {     //winner here has null value.
+    let winner = null;
+                                        //conditions to check that winner by horizontal move, vertical move. diagonal move.
+    // horizontal
+    for (let m = 0; m < 3; m++) {
+      if (equals3(board[m][0], board[m][1], board[m][2])) {
+        winner = board[m][0];
+      }
+    }
+
+    // Vertical
+    for (let m = 0; m < 3; m++) {
+      if (equals3(board[0][m], board[1][m], board[2][m])) {
+        winner = board[0][m];
+      }
+    }
+
+    // Diagonal
+    if (equals3(board[0][0], board[1][1], board[2][2])) {
+      winner = board[0][0];
+    }
+    if (equals3(board[2][0], board[1][1], board[0][2])) {
+      winner = board[2][0];
+    }
+
+    let openSpots = 0;
+    for (let m = 0; m < 3; m++) {
+      for (let n = 0; n < 3; n++) {
+        if (board[m][n] == '') {
+          openSpots++;
+        }
+      }
+    }
+
+    if (winner == null && openSpots == 0) { //if sopt has 0 value and winner value is also 0 then the game is tie 
+    //on the other hand if the spot return some value and winner too return the winner 
+      return 'tie';
+    } else {
+      return winner;
+    }
+  }
+
+  function mousePressed() {
+    if (currentPlayer == human) {
+      // Human make turn
+      let m = floor(mouseX / w);
+      let n = floor(mouseY / h);
+      // If valid turn
+      if (board[m][n] == '') {
+        board[m][n] = human;
+        currentPlayer = computer;
+        bestMove();
+      }
+    }
+  }
+
+  function draw() {
+    background(255);
+    strokeWeight(4);
+
+    line(w, 0, w, height);
+    line(w * 2, 0, w * 2, height);
+    line(0, h, width, h);
+    line(0, h * 2, width, h * 2);
+
+    for (let n = 0; n < 3; n++) {
+      for (let m = 0; m < 3; m++) {
+        let x = w * m + w / 2;
+        let y = h * n + h / 2;
+        let spot = board[m][n];
+        textSize(32);
+        let r = w / 4;
+        if (spot == human) {
+          noFill();
+          ellipse(x, y, r * 2);
+        } else if (spot == computer) {
+          line(x - r, y - r, x + r, y + r);
+          line(x + r, y - r, x - r, y + r);
+        }
+      }
+    }
+
+    let result = checkWinner();
+    if (result != null) {
+      noLoop();
+      let resultP = createP('');
+      resultP.style('font-size', '32pt');
+      if (result == 'tie') {
+        resultP.html('Tie!');
+      } else {
+        resultP.html(`${result} wins!`);
+      }
+    }
+  }
+
+  function bestMove() {
+  // computer to make its turn
+  // maximizer takes first turn which has worst-case initial value =- infinity
+  // Minimizer will take next turn which has worst-case initial value = +infinity.
+  let bestScore = -Infinity;
+  let move;
+  for (let m = 0; m < 3; m++) {
+    for (let n = 0; n < 3; n++) {
+      // Is the spot available?
+      if (board[m][n] == '') {
+        board[m][n] = computer;
+        let score = minimax(board, 0, false);
+        board[m][n] = '';
+        if (score > bestScore) {
+          bestScore = score;
+          move = { m, n };
+        }
+      }
+    }
+  }
+  board[move.m][move.n] = computer;
+  currentPlayer = human;
+}
+
+let scores = {
+  X: 10,
+  O: -10,
+  tie: 0
+};
+
+function minimax(board, depth, isMaximizing) {
+  let result = checkWinner();
+  if (result !== null) {
+    return scores[result];
+  }
+//Maxmizing function. (Maximizer will try to get the Maximum possible score.)
+  if (isMaximizing) {
+    let bestScore = -Infinity;
+    for (let m = 0; m < 3; m++) {
+      for (let n = 0; n < 3; n++) {
+        // Is the spot available?
+        if (board[m][n] == '') {
+          board[m][n] = computer;
+          let score = minimax(board, depth + 1, false);
+          board[m][n] = '';
+          bestScore = max(score, bestScore);  //return the max score 
+        }
+      }
+    }
+    return bestScore;
+  } else {
+    //Minimizing function (Minimizer will try to get the minimum possible score.)
+    let bestScore = Infinity;
+    for (let m = 0; m < 3; m++) {
+      for (let n = 0; n < 3; n++) {
+        // Is the spot available?
+        if (board[m][n] == '') {
+          board[m][n] = human;
+          let score = minimax(board, depth + 1, true);
+          board[m][n] = '';
+          bestScore = min(score, bestScore);
+        }
+      }
+    }
+    return bestScore;
+  }
+}