Java Notes
Kilometer to Miles - Formatted
This program is the same as Example: Dialog: Kilometers to Miles, but it formats the output to display the output to only one decimal place. It also shows how to define a constant.
Source code
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// File : intro-dialogKmToMiles.java // Purpose: Converts kilometers to miles. Formats output. // Author : Michael Maus // Date : 16 Apr 2005 import javax.swing.*; // Package containing JOptionPane import java.text.*; // Package containing DecimalFormat public class KmToMilesFormatted { //... Static constants static final double MILES_PER_KILOMETER = 0.621; //Note 1 static final DecimalFormat ONE_DECIMAL_PLACE = new DecimalFormat("0.0"); //Note 2 public static void main(String[] args) { //... Variables String kmStr; // String version of km before conversion to double. double kilometers; // Number of kilometers. double miles; // Number of miles. //... Input kmStr = JOptionPane.showInputDialog(null, "Enter number of kilometers."); kilometers = Double.parseDouble(kmStr); //... Computation miles = kilometers * MILES_PER_KILOMETER; //... Output JOptionPane.showMessageDialog(null, kilometers + " kilometers is " + ONE_DECIMAL_PLACE.format(miles) + " miles."); } } |
Notes
Note 1: Constant values are commonly declared static final before the methods are defined.
Note 2: The string pattern that's passed to the DecimalFormat constructor shows how many digits are printed after the decimal point.