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// intro-dialog/KmToMilesMethod.java // Convert kilometers to miles using a method. JOptionPane IO. // Michael Maus, 28 Oct 2004 import javax.swing.*; public class KmToMilesMethod { //================================================================= main public static void main(String[] args) { //... Local variables String kmStr; // String km before conversion to double. double km; // Number of kilometers. double mi; // Number of miles. //... Input kmStr = JOptionPane.showInputDialog(null, "Enter kilometers."); km = Double.parseDouble(kmStr); //... Computation mi = convertKmToMi(km); //Note 1 //... Output JOptionPane.showMessageDialog(null, km + " kilometers is " + mi + " miles."); //... Stop System.exit(0); // Stop GUI program } //========================================================= convertKmToMi public static double convertKmToMi(double kilometers) { // Assume there are 0.621 miles in a kilometer. double miles = kilometers * 0.621; return miles; } } |
Note 1: Call a function to do the conversion. Altho this function is trivial, just a multiplication, it is very good practice to separate the "model" or "logic" of the program from user interface. As programs become larger, this separation becomes essential.