Switching Turns

After a move, we need to switch whose turn it is.

The NOT Operator (!):

The ! operator flips a boolean value.

• !true becomes false

• !false becomes true

Example:

isActive = !isActive;

If isActive was true, it becomes false. If it was false, it becomes true.

For Our Game:

After placing a piece, toggle xTurn to switch to the other player:

xTurn = !xTurn;

If it was X's turn (true), it becomes O's turn (false), and vice versa.

Add this line at the end of makeMove to switch turns after each move.

Toggle turn after move

Requirements:

Toggles xTurn with NOT operator

Toggle comes after board assignment

Inside makeMove function

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract TicTacToe {
    address public playerX;
    address public playerO;

    enum Cell { Empty, X, O }

    Cell[9] public board;

    bool public xTurn;

    function startGame(address _opponent) public {
        playerX = msg.sender;
        playerO = _opponent;
        xTurn = true;
    }

    function makeMove(uint _position) public {
        require(board[_position] == Cell.Empty, "Cell already taken");

        Cell piece = xTurn ? Cell.X : Cell.O;
        board[_position] = piece;
    }
}