# Computer Constantly Taking Turn in Tic-Tac-Toe Game

**URL:** <https://discourse.processing.org/t/computer-constantly-taking-turn-in-tic-tac-toe-game/43467>\
**Category:** Coding Questions\
**Created:** [December 13, 2023, 4:05pm UTC](https://discourse.processing.org/t/computer-constantly-taking-turn-in-tic-tac-toe-game/43467 "2023-12-13T16:05:15Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![XeroX\_ing](https://avatars.discourse-cdn.com/v4/letter/x/7ba0ec/32.png) [@XeroX\_ing](https://discourse.processing.org/u/XeroX_ing)\
**Post date:** [December 13, 2023, 4:05pm UTC](https://discourse.processing.org/t/computer-constantly-taking-turn-in-tic-tac-toe-game/43467/1 "2023-12-13T16:05:15Z")

</div>

Hello again! I’m trying to make a tic tac toe game against a computer, where the user enters their choice using number inputs instead of mouseclicks. Edit, I’ve gotten the computer to stop constantly taking its turn, but now player input is returning the “Incorrect key pressed! Please select an empty space.” error every time the player makes a move. Additionally, if the computer hits a full space, it does not reroll until it finds an empty space. How do I fix this?

```auto

void setup() {
  size(500, 500);
  background(255, 255, 255);
  ticTacToeBoard();
  nestedForLoopToPopulateGameBoard();
  System.out.println("Press a number from 0 to 8");

}

void draw() {
  if(keyPressed == true){    
      keyPressed();
      keyReleased(); 
      delay(100);
      gameLogic();
  }
} 

Random randomizer = new Random();
  
void nestedForLoopToPopulateGameBoard() {
   for(int row = 0; row<3; row++)
     for(int col = 0; col<3; col++)
       gameBoard[row][col] = ' ';
}
      
void gameLogic() {  
    computerMove = new Random().nextInt(9+1);
    
  //if(playerCurrentTurn == false){
        switch(computerMove) {
    case 1:
    if(gameBoard[0][0] != moveTokenO)
      if(gameBoard[0][0] != moveTokenX) {
         strokeWeight(2);
         line(0,0,165,165);
         line(165,0,0,165);
       gameBoard[0][0] = moveTokenX;
       System.out.println(gameBoard[0][0]);
        } else { 
         gameLogic();
       }
       break;
     case 2:
     if(gameBoard[0][1] != moveTokenO) 
       if(gameBoard[0][1] != moveTokenX) {
         strokeWeight(2);
         line(165,0,330,165);
         line(330,0,165,165);
       gameBoard[0][1] = moveTokenX;
       System.out.println(gameBoard[0][1]);
         } else { 
         gameLogic();
       }
       break;
    case 3:
    if(gameBoard[0][2] != moveTokenO) 
      if(gameBoard[0][2] != moveTokenX) {
         strokeWeight(2);
         line(330,0,500,165);
         line(500,0,330,165);
       gameBoard[0][2] = moveTokenX;
       System.out.println(gameBoard[0][2]);
        } else { 
         gameLogic();
       }
       break;
    case 4:
    if(gameBoard[1][0] != moveTokenO) 
    if(gameBoard[1][0] != moveTokenX) {
         strokeWeight(2);
         line(0,165,165,330);
         line(165,165,0,330);
       gameBoard[1][0] = moveTokenX;
       System.out.println(gameBoard[1][0]);
        } else { 
         gameLogic();
       }
       break;
    case 5:
    if(gameBoard[1][1] != moveTokenO) 
    if(gameBoard[1][1] != moveTokenX) {
         strokeWeight(2);
         line(165,165,330,330);
         line(330,165,165,330);
         gameBoard[1][1] = moveTokenX;
       System.out.println(gameBoard[1][1]);
        } else { 
         gameLogic();
       }
       break;
    case 6:
    if(gameBoard[1][2] != moveTokenO) 
      if(gameBoard[1][2] != moveTokenX) {
         strokeWeight(2);
         line(330,165,500,330);
         line(500,165,330,330);
       gameBoard[1][2] = moveTokenX;
       System.out.println(gameBoard[1][2]);
        } else { 
         gameLogic();
       }
       break;
    case 7:
    if(gameBoard[2][0] != moveTokenO) 
    if(gameBoard[2][0] != moveTokenX) {
         strokeWeight(2);
         line(165,330,0,500);
         line(0,330,165,500);
       gameBoard[2][0] = moveTokenX;
       System.out.println(gameBoard[2][0]);
        } else { 
         gameLogic();
       }
       break;
    case 8:
    if(gameBoard[2][1] != moveTokenO)
    if(gameBoard[2][1] != moveTokenX) {
         strokeWeight(2);
         line(165,330,330,500);
         line(330,330,165,500);
       gameBoard[2][1] = moveTokenX;
       System.out.println(gameBoard[2][1]);
        } else { 
         gameLogic();
       }
       break;
    case 9:
    if(gameBoard[2][2] != moveTokenO) 
    if(gameBoard[2][2] != moveTokenX) {
         strokeWeight(2);
         line(500,330,330,500);
         line(330,330,500,500);
       gameBoard[2][2] = moveTokenX;
       System.out.println(gameBoard[2][2]);
        } else { 
         gameLogic();
       }
       break;
  }    
  System.out.println(computerMove); 
  
     }
  
void keyPressed() {
  circle = createShape(ELLIPSE, 70, 70, 150, 150);
 //if(playerCurrentTurn == true) {
 if(keyPressed == true)
  switch(key) {
    case '0':
       if(gameBoard[0][0] != moveTokenX) {
             if(gameBoard[0][0] != moveTokenO){
         gameBoard[0][0] = moveTokenO;
       shape(circle, 10, 10);
       System.out.println(gameBoard[0][0]);
       delay(50);
             }
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '1':
    if(gameBoard[0][1] != moveTokenX) 
      if(gameBoard[0][1] != moveTokenO){
       gameBoard[0][1] = moveTokenO;
       shape(circle, 180, 10);
       System.out.println(gameBoard[0][1]);
       delay(50);
    } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '2':
    if(gameBoard[0][2] != moveTokenX) 
          if(gameBoard[0][2] != moveTokenO){
       gameBoard[0][2] = moveTokenO;
       shape(circle, 350, 10);
       System.out.println(gameBoard[0][2]);
       delay(50);
    } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '3':
        if(gameBoard[1][0] != moveTokenX) 
              if(gameBoard[1][0] != moveTokenO){
       gameBoard[1][0] = moveTokenO;
       shape(circle, 10, 180);
       System.out.println(gameBoard[1][0]);
       delay(50);
        } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '4':
       if(gameBoard[1][1] != moveTokenX) 
             if(gameBoard[1][1] != moveTokenO){
       gameBoard[1][1] = moveTokenO;
       shape(circle, 180, 180);
       System.out.println(gameBoard[1][1]);
       delay(50);
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '5':
       if(gameBoard[1][2] != moveTokenX) 
             if(gameBoard[1][2] != moveTokenO){
       gameBoard[1][2] = moveTokenO;
       shape(circle, 350, 180);
       System.out.println(gameBoard[1][2]);
       delay(50);
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '6':
       if(gameBoard[2][0] != moveTokenX) 
             if(gameBoard[2][0] != moveTokenO){
       gameBoard[2][0] = moveTokenO;
       shape(circle, 10, 350);
       System.out.println(gameBoard[2][0]);
       delay(50);
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '7':
       if(gameBoard[2][1] != moveTokenX) 
             if(gameBoard[2][1] != moveTokenO){
       gameBoard[2][1] = moveTokenO;
       shape(circle, 180, 350);
       System.out.println(gameBoard[2][1]);
       delay(50);
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    case '8':
       if(gameBoard[2][2] != moveTokenX) 
             if(gameBoard[2][2] != moveTokenO){
       gameBoard[2][2] = moveTokenO;
       shape(circle, 350, 350);
       System.out.println(gameBoard[2][2]);
       delay(50);
       } else { 
         println("Incorrect key pressed! Please select an empty space.");
       }
       break;
    default: // catches numbers outside of 0-8
       println("Incorrect key pressed! Please select a key between 0-8"); 
       delay(50);
       break;  
  }
}
//}

void keyReleased() {
  playerCurrentTurn = true;
  delay(50);
  playerCurrentTurn = false;
  delay(5);

}

```

---

<div class="post-metadata">

**Author:** ![Chrisir](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/chrisir/32/45_2.png) [@Chrisir](https://discourse.processing.org/u/Chrisir)\
**Post date:** [December 13, 2023, 6:09pm UTC](https://discourse.processing.org/t/computer-constantly-taking-turn-in-tic-tac-toe-game/43467/2 "2023-12-13T18:09:04Z")

</div>

A few points here.

```auto
    keyPressed();
    keyReleased();

```

both get called automatically.

So no need to call them in `draw()`.

The line `if (keyPressed == true) {`  
is not needed because the funcs get called only when a key is pressed anyway.

I suggest

```auto
void draw() {
  background(255, 255, 255);
  delay(100);
  if (PC_MOVE)
    gameLogic();
  ticTacToeBoard();
}

```

The new var PC\_MOVE is a boolean that is true or false. It indicates whether the human or the PC has to move.

declare it before setup() like `boolean PC_MOVE = true;`

- After each successful human move please say `PC_MOVE = true;`
- After each successful PC move please say `PC_MOVE = false;`

(technically, gameLogic is not the correct term, better `pcMove()` or `ai_move()`)

**Reroll**

> [@XeroX\_ing](#):
>
> if the computer hits a full space, it does not reroll until it finds an empty space.

I think with my logic this is solved because `draw()` runs on and on so gameLogic() is called again and again until `PC_MOVE == false`.

But let me explain within your attempt:

You attempt to call gameLogic() from gameLogic() which is neat (recursive).

When you look closely at your if-clause in gameLogic(), there is an error though :

> [@XeroX\_ing](#):
>
> ```auto
> if(gameBoard[1][0] != moveTokenO) 
> if(gameBoard[1][0] != moveTokenX) {
> do something
> } else { 
> gameLogic();
> }
> break;
> 
> ```

Since the first if has no { bracket, the entire block hangs on the first if.  
When you would add the brackets it’d read:

```auto
    if(gameBoard[1][0] != moveTokenO) {
        if(gameBoard[1][0] != moveTokenX) {
                 do something
            } else { 
             gameLogic();
           }//else
    }//outer if
       break;

```

Now you can see that the “else gameLogic()”-section applies only to the inner if-clause and not to the outer one.

Hence,gameLogic() is only called when the outer if is true, and the inner if is false. Not when the outer if is false. Bad.

A fix: Give the outer if-clause its own else block:

```auto
    if(gameBoard[1][0] != moveTokenO) {
        if(gameBoard[1][0] != moveTokenX) {
                 do something
            } else { 
             gameLogic();
           }
    } else { 
             gameLogic();
    }
    break;

```

OR use && in the first place. AND

```auto
    if(gameBoard[1][0] != moveTokenO && 
        gameBoard[1][0] != moveTokenX) {
                 do something
            } else { 
             gameLogic();
           }
       break;

```

There are several other ways.  
For example set a flag `boolean moveSuccessful=false;` and after the entire switch() section say

```auto
if(moveSuccessful == false) {
   gameLogic();
}

```

So you can get rid of **all** other else-gameLogic()-clauses in the function.

**Remark 1**

- please use ctrl-t when programming, auto indents. Especially before posting in the forum.

- _please always post a runnable version of your Sketch so that we can check it_

**Remark 2**

in the func `keyPressed()` this is not needed: ` if (keyPressed == true)`

Chrisir