import java.awt.*;import java.awt.event.*;import java.util.*;import java.applet.Applet;

class Unit {    String description;    double multiplier;    Unit(String description, double multiplier)     {        super();        this.description = description;        this.multiplier = multiplier;    }}

class CPanel extends Panel implements ActionListener,		                 AdjustmentListener,		                 ItemListener{    TextField TEnter;    Choice Cchoose;        int max = 10000;       Converter handle;    Unit[] units;    CPanel(Converter myController, String myTitle, Unit[] myUnits)     {        GridBagConstraints c = new GridBagConstraints();        GridBagLayout gridbag = new GridBagLayout();        setLayout(gridbag);        handle = myController;        units = myUnits;        c.fill = GridBagConstraints.HORIZONTAL;        Label label = new Label(myTitle, Label.CENTER);         c.gridwidth = GridBagConstraints.REMAINDER;        gridbag.setConstraints(label, c);        add(label);                TEnter = new TextField("0", 10);         c.weightx = 1.0;        c.gridwidth = 1;        gridbag.setConstraints(TEnter, c);        add(TEnter);	TEnter.addActionListener(this);        Cchoose = new Choice();         for (int i = 0; i < units.length; i++)         {            Cchoose.add(units[i].description);        }        c.weightx = 0.0;        c.gridwidth = GridBagConstraints.REMAINDER;         gridbag.setConstraints(Cchoose, c);        add(Cchoose);	Cchoose.addItemListener(this);    
	c.gridwidth = 1;           }    double getMultiplier()     {        int i = Cchoose.getSelectedIndex();        return units[i].multiplier;    }    public void paint(Graphics g)     {        Dimension d = getSize();        g.drawRect(0,0, d.width - 1, d.height - 1);    }            public Insets getInsets()     {        return new Insets(5,5,5,8);    }    double getValue()     {        double f;        try         {            f = (double)Double.valueOf(TEnter.getText()).doubleValue();         }         catch (java.lang.NumberFormatException e)         {            f = 0.0;        }        return f;    }    public void actionPerformed(ActionEvent e)     {        setSliderValue(getValue());        handle.Exchange(this);    }    public void itemStateChanged(ItemEvent e)     {        handle.Exchange(this);    }    public void adjustmentValueChanged(AdjustmentEvent e)     {        TEnter.setText(String.valueOf(e.getValue()));        handle.Exchange(this);    }    void setValue(double f)     {        setSliderValue(f);        TEnter.setText(String.valueOf((float)f));    }    void setSliderValue(double f)     {        int sliderValue = (int)f;        if (sliderValue > max)               sliderValue = max;        if (sliderValue < 0)            sliderValue = 0;    }}
public class Converter extends Applet {    private CPanel MPanel, UPanel;    private Unit[] ChoiceM = new Unit[3];    private Unit[] ChoiceU = new Unit[4];    public void init()     {        setLayout(new GridLayout(2,0,5,5));        ChoiceM[0] = new Unit("公分", 0.01);        ChoiceM[1] = new Unit("公尺", 1.0);        ChoiceM[2] = new Unit("公里", 1000.0);        MPanel = new CPanel(this, "公制",ChoiceM);        MPanel.setBackground(Color.white);                ChoiceU[0] = new Unit("英吋", 0.0254);        ChoiceU[1] = new Unit("英呎", 0.305);        ChoiceU[2] = new Unit("碼", 0.914);        ChoiceU[3] = new Unit("英哩", 1613.0);                UPanel = new CPanel(this, "英制", ChoiceU);        UPanel.setBackground(Color.white);        add(MPanel);        add(UPanel);    }    void Exchange(CPanel from) {        CPanel to;        if (from == MPanel)            to = UPanel;        else            to = MPanel;        double multiplier = from.getMultiplier() / to.getMultiplier();        to.setValue(multiplier * from.getValue());    }    public void paint(Graphics g)     {        Dimension d = getSize();        g.drawRect(0,0, d.width - 1, d.height - 1);    }            public Insets getInsets()     {        return new Insets(5,5,5,5);    }    }