main.cpp

bool isWin(char game[3][3]){
	bool win = false;
	if (game[0][0] == game[0][1] && game[0][1] == game[0][2] && (game[0][0] == 'X' || game[0][0] == 'O')) win = true;
	if (game[1][0] == game[1][1] && game[1][1] == game[1][2] && (game[1][0] == 'X' || game[1][0] == 'O')) win = true;
	if (game[2][0] == game[2][1] && game[2][1] == game[2][2] && (game[2][0] == 'X' || game[2][0] == 'O')) win = true;
	// column
	if (game[0][0] == game[1][0] && game[1][0] == game[2][0] && (game[0][0] == 'X' || game[0][0] == 'O')) win = true;
	if (game[0][1] == game[1][1] && game[1][1] == game[2][1] && (game[0][1] == 'X' || game[0][1] == 'O')) win = true;
	if (game[0][2] == game[1][2] && game[1][2] == game[2][2] && (game[0][2] == 'X' || game[0][2] == 'O')) win = true;
	// diagonal
	if (game[0][0] == game[1][1] && game[1][1] == game[2][2] && (game[0][0] == 'X' || game[0][0] == 'O')) win = true;
	if (game[0][2] == game[1][1] && game[1][1] == game[2][0] && (game[0][2] == 'X' || game[0][2] == 'O')) win = true;
	return win;
}


int main(){
	int i, j;
	char game[3][3] = {' '}; // Tic-tac-toe
	char player1 = 'X';
	char player2 = 'O';
	bool turn = true; // false for player 1's turn, true for player 2's turn. Player 1 first.
	cout << "X = Player 1" << endl << "O = Player 2" << endl;
       for (int n=0; n<9; n++){
			turn = !turn;  // use the not-operator to change true to false or false to true.
		    if (turn == false)
				cout << "Player 1: ";
			else
				cout << "Player 2: ";
			cout << "Which cell to mark? i:[1..3], j:[1..3]: "; 
			cin >> i >> j;
			if (turn == false)
			   game[i][j] = 'X';
			else 
			   game[i][j] = 'O';
			if (isWin(game)){
				cout << "Win!" << endl;
				break; // need to terminate the problem
			}
		}
	if (i==3) // all celles with i=0 to 2 have been inputted above but no winner yet
	   cout << "Tie!" << endl;

	// show the game to console
	cout << game[0][0] << " " << game[0][1] << " " << game[0][2] << endl;
	cout << game[1][0] << " " << game[1][1] << " " << game[1][2] << endl;
	cout << game[2][0] << " " << game[2][1] << " " << game[2][2] << endl;
	return 0;
}