import acm.graphics.*;
import acm.program.*;

public class Checkerboard extends GraphicsProgram {

    public void run() {
        double sqSize = (double) getHeigth() / N_ROWS;

        for (int i = 0; i < N_ROWS; i++) {
            for (int j = 0; j < N_ROWS; j++) {
                double x = j * sqSize;
                double y = i * sqSize;

                drawGRect(x, y, sqSize);
            }
        }
    }

    private void drawGRect(double x, double y, double sqSize) {
        GRect sq = new GRect(x, y, sqSize, sqSize);
        sq.setFilled((i + j) % 2 != 0);
        add(sq);
    }


/* Private constants. */
    private static final int N_ROWS = 8;
    private static final int N_COLUMNS = 8;
}