java

/**
 *
 */
import javax.swing.*;
import java.awt.*;
/**
 * @author reedpl1
 *
 */
public class GPACalcDriver {

	/**
	 * @param args
	 */
	public static void main(String[] args)
	{
		GPACalcGUI gc = new GPACalcGUI();

	}

}

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/**
 *
 */
import javax.swing.*;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
/**
 * @author reedpl1
 *
 */
public class GPACalcGUI extends JFrame
{
	private static final long serialVersionUID = 1L;
	private JPanel panel;
	private JLabel label1,
				   label2,
				   label3;
	private JButton calculate;
	private JButton quit;
	private final int WINDOW_WIDTH = 190;
	private final int WINDOW_HEIGHT = 153;
	private JTextField cred;
	private JTextField hour;
	private JTextField gpa;
	/**
	 * @param args
	 * @return
	 */
	public GPACalcGUI()
	{
		super("GPA Calculator");
		cred = new JTextField(4);
		hour = new JTextField(4);
		gpa  = new JTextField(4);
		setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		label1 = new JLabel("Credits Completed");
		label2 = new JLabel("Hours completed   ");
		label3 = new JLabel("GPA                           ");

		calculate = new JButton("Calculate");
		quit = new JButton("Quit");

		calculate.addActionListener(new CalculateListener());
		quit.addActionListener(new QuitListener());
		panel = new JPanel();
		panel.add(label1);
		panel.add(cred);
		panel.add(label2);
		panel.add(hour);
		panel.add(label3);
		panel.add(gpa);
		panel.add(calculate);
		panel.add(quit);

		add(panel);
		setLocationRelativeTo(null);
		setVisible(true);
	}
	private class CalculateListener implements ActionListener
	{
		@Override
		public void actionPerformed(ActionEvent arg0)
		{
			DecimalFormat df = new DecimalFormat("0.00");
			double calculatedGPA;
			calculatedGPA = (Double.parseDouble(cred.getText())) / (Double.parseDouble(hour.getText()));
			gpa.setText(new Double(df.format(calculatedGPA)).toString());
		}
	}
	private class QuitListener implements ActionListener
	{
		@Override
		public void actionPerformed(ActionEvent arg0)
		{
			JOptionPane.showMessageDialog(null, "Thank you for using the program.");
			System.exit(0);
		}
	}
}