// KmToMilesMethods.java -- Converts kilometers to miles.
// Michael Maus, 9 Sept 2004
//
// Note: Move input methods to their own class.

import javax.swing.*;
import java.text.*;

public class KmToMilesInputClass {
    
    public static void main(String[] args) {
        //... Constants
        final double MILES_PER_KILOMETER = 0.621;
        final DecimalFormat ONE_DECIMAL_PLACE = new DecimalFormat("0.0");
        
        //... Variables
        double kilometers;  // Number of kilometers.
        double miles;       // Number of miles.
        IOHandler io;
        
        //... Initialization
        io = new IOHandler();
        
        //... Input
        kilometers = io.getDouble("Enter number of kilometers.");
        
        //... Computation
        miles = kilometers * MILES_PER_KILOMETER;
        
        //... Output
        io.putString(kilometers + " kilometers is "
                   + ONE_DECIMAL_PLACE.format(miles) + " miles.");
        
        //... Stop
        System.exit(0);  // Stop GUI program
    }
}


class IOHandler {
    public double getDouble(String prompt) {
        String tempStr;
        tempStr = JOptionPane.showInputDialog(null, prompt);
        return Double.parseDouble(tempStr);
    }
    
    
    public void putString(String output) {
        JOptionPane.showMessageDialog(null, output);
    }
}