Tic Tac Toe - Java

Question

I am making a Tic Tac Toe game in Java and I need to set the "X" value so that on the 1st, 3rd, 5th, 7th and 9th turn an X is placed in the boxes and when it's the 2nd, 4th, 6th and 8th turn a "O" is placed. If anyone could help it would greatly appreciated

I tried using a counter:

public void onClick(View event) {
    // TODO Auto-generated method stub
    if (event == btnBox1) {
        counter++;
        if (counter == 0) {
            btnBox1.setText("X");
            btnBox1.setEnabled(false);
        }

        if (counter == 1) {
            btnBox1.setText("O");
            btnBox1.setEnabled(false);
        }

        // ...
    }

    // ...
}

Answer 1

There are two ways to do it:

• the remainder or modulus % operator. It returns the remainder of the division of two numbers. counter % 2 will be 1 if counter is odd and 0 if counter is even.
• the bitwise AND operator &, suggested by Mr. Polywhirl. You could also do (n & 1) == 0 (bit-wise AND) to check for even.

Using the modulus operator, your method will be:

public void onClick(View event) { 
    if (event == btnBox1){ 
        counter++; 
        if (counter % 2 == 0){ 
            btnBox1.setText("X"); 
            btnBox1.setEnabled(false); 
        }
        if (counter % 2 == 1){
            btnBox1.setText("O");
            btnBox1.setEnabled(false);
        }
    }
}