import java.awt.*;		// for Graphics, Color
import javax.swing.*;	// for JFrame, JPanel

public class Ch13_3b		// draw a Checkerboard using JButtons
{
	public static void main(String[] args)	
	{
		JFrame frame=new JFrame("Exercise12_1");				// establish title for JFrame
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	// establish what to do if JFrame is closed
		frame.setSize(340,360);									// set size to something reasonable for this GUI
		JPanel p1=new JPanel(new GridLayout(8,8));	// we will insert 64 JButtons into an 8x8 grid
		JButton[][] b=new JButton[8][8];			// create an 8x8 array for the JButtons
		for(int i=0;i<8;i++)	
			for(int j=0;j<8;j++)
			{
				b[i][j]=new JButton();				// create the next JButton, notice we pass nothing to the constructor
				b[i][j].setPreferredSize(new Dimension(40,40));   // set its size and color
				if((i+j)%2==0) b[i][j].setBackground(Color.RED);
				else b[i][j].setBackground(Color.BLACK);
				p1.add(b[i][j]);					// add it to the JPanel
			}
		frame.add(p1);					// add the JPanel to this JFrame and make the JFrame visible
		frame.setVisible(true);		
	}
}