Qt Reference Documentation

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# tic-tac-toe.js Example File

declarative/toys/tic-tac-toe/qml/tic-tac-toe/content/tic-tac-toe.js

     function winner(board)
     {
         for (var i=0; i<3; ++i) {
             if (board.children[i].state != ""
                     && board.children[i].state == board.children[i+3].state
                     && board.children[i].state == board.children[i+6].state)
                 return true

             if (board.children[i*3].state != ""
                     && board.children[i*3].state == board.children[i*3+1].state
                     && board.children[i*3].state == board.children[i*3+2].state)
                 return true
         }

         if (board.children[0].state != ""
                 && board.children[0].state == board.children[4].state != ""
                 && board.children[0].state == board.children[8].state != "")
             return true

         if (board.children[2].state != ""
                 && board.children[2].state == board.children[4].state != ""
                 && board.children[2].state == board.children[6].state != "")
             return true

         return false
     }

     function restartGame()
     {
         game.running = true

         for (var i=0; i<9; ++i)
             board.children[i].state = ""
     }

     function makeMove(pos, player)
     {
         board.children[pos].state = player
         if (winner(board)) {
             gameFinished(player + " wins")
             return true
         } else {
             return false
         }
     }

     function canPlayAtPos(pos)
     {
         return board.children[pos].state == ""
     }

     function computerTurn()
     {
         var r = Math.random();
         if (r < game.difficulty)
             smartAI();
         else
             randomAI();
     }

     function smartAI()
     {
         function boardCopy(a) {
             var ret = new Object;
             ret.children = new Array(9);
             for (var i = 0; i<9; i++) {
                 ret.children[i] = new Object;
                 ret.children[i].state = a.children[i].state;
             }
             return ret;
         }

         for (var i=0; i<9; i++) {
             var simpleBoard = boardCopy(board);
             if (canPlayAtPos(i)) {
                 simpleBoard.children[i].state = "O";
                 if (winner(simpleBoard)) {
                     makeMove(i, "O")
                     return
                 }
             }
         }
         for (var i=0; i<9; i++) {
             var simpleBoard = boardCopy(board);
             if (canPlayAtPos(i)) {
                 simpleBoard.children[i].state = "X";
                 if (winner(simpleBoard)) {
                     makeMove(i, "O")
                     return
                 }
             }
         }

         function thwart(a,b,c) {    //If they are at a, try b or c
             if (board.children[a].state == "X") {
                 if (canPlayAtPos(b)) {
                     makeMove(b, "O")
                     return true
                 } else if (canPlayAtPos(c)) {
                     makeMove(c, "O")
                     return true
                 }
             }
             return false;
         }

         if (thwart(4,0,2)) return;
         if (thwart(0,4,3)) return;
         if (thwart(2,4,1)) return;
         if (thwart(6,4,7)) return;
         if (thwart(8,4,5)) return;
         if (thwart(1,4,2)) return;
         if (thwart(3,4,0)) return;
         if (thwart(5,4,8)) return;
         if (thwart(7,4,6)) return;

         for (var i =0; i<9; i++) {
             if (canPlayAtPos(i)) {
                 makeMove(i, "O")
                 return
             }
         }
         restartGame();
     }

     function randomAI()
     {
         var unfilledPosns = new Array();

         for (var i=0; i<9; ++i) {
             if (canPlayAtPos(i))
                 unfilledPosns.push(i);
         }

         if (unfilledPosns.length == 0) {
             restartGame();
         } else {
             var choice = unfilledPosns[Math.floor(Math.random() * unfilledPosns.length)];
             makeMove(choice, "O");
         }
     }

     function gameFinished(message)
     {
         messageDisplay.text = message
         messageDisplay.visible = true
         game.running = false
     }