// File: FahrenheitToCelsius.java
// Simple GUI example
// Prepared by Dr. Spiegel

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

class ConvertTemperatures extends JFrame
  implements ActionListener, WindowListener
{ JLabel directions;
  JTextField fahrenheit;
  JLabel celsius;

  ConvertTemperatures(String s)
  { super(s);
    // Need a JPanel to put items on. We'll use a BorderLayout
    JPanel panel=new JPanel(new BorderLayout(5,5));

    // Set JFrame size. If you don't do this, only the top bar will appear
    setSize(250,100);

    // Set JPanel size
    panel.setSize(250,130);

    // Set the JPanel's background
    panel.setBackground(Color.blue);

    // Add a window listener to the JFrame
    addWindowListener(this);

    // Now, place everything into the JPanel
    // First, the prompt
    directions = new JLabel("Enter temperature in Fahrenheit:");
    directions.setForeground(Color.yellow);
    panel.add("West",directions);

    // Now, the text field to input the temperature
    fahrenheit = new JTextField(2);
    fahrenheit.setSize(15,10);

    // Place it on the panel. Note, that if you don't want it to appear as
    //       tall as it does, you should place the JTextField into a JPanel
    //       with a FlowLayout and then that new JPanel into the main JPanel
    panel.add("East",fahrenheit);

    // Need a listener for events on the text field
    fahrenheit.addActionListener(this);

    // Add a label to hold the result
    celsius = new JLabel("                             ");
    celsius.setFont(new Font("TimesRoman 16 point bold.", 20, 25));
    celsius.setForeground(Color.red);
    panel.add("South",celsius);

    // Place the JPanel on the JFrame
    getContentPane().add(panel);
    setVisible(true);
  }

  public void windowClosed(WindowEvent event) {}
  public void windowDeiconified(WindowEvent event) {}
  public void windowIconified(WindowEvent event) {}
  public void windowActivated(WindowEvent event) {}
  public void windowDeactivated(WindowEvent event) {}
  public void windowOpened(WindowEvent event) {}
  public void windowClosing(WindowEvent event) { System.exit(0); }

  public void actionPerformed(ActionEvent event)
  { int f = Integer.parseInt(fahrenheit.getText());
    long c = Math.round(5.0*(f - 32)/9.0);
    fahrenheit.setText("");
    celsius.setText(f + "\u00B0F = " + c + "\u00B0C");
  }
}

class TestConvertTemperatures
{ public static void main(String[] args)
  { new ConvertTemperatures("Fahrenheit To Celsius Conversion");
  }
}