# Java Notes

# Java Example: Console: Kilometers to Miles

This program asks the user for a number of miles and converts it to kilometers.

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    // File   : examples/console/KmToMilesConsole.java
    // Description: Converts kilometers to miles.
    // Illustrates: Console IO for read-compute-write program, named constants.
    // Author : Fred Swartz - 2007-01-18 - Placed in public domain.

    import java.util.*;  // Package containing Scanner

    public class KmToMilesConsole {
        //==================================================================== constants
        static final double MILES_PER_KILOMETER = 0.621;                       //Note 1

        //========================================================================= main
        public static void main(String[] args) {
            Scanner in = new Scanner(System.in);                               //Note 2

            //... Input
            System.out.print("Enter number of kilometers: ");
            double kilometers = in.nextDouble();

            //... Computation
            double miles = kilometers * MILES_PER_KILOMETER;

            //... Output
            System.out.println(kilometers + " kilometers is " + miles + " miles.");
        }
    }

### Notes

1. Constant values are commonly declared static final before the methods are defined. The 'static' keyword will be explained later. If a variable is defined with the 'final' attribute, it's value can't be changed after an assignment to it, which is exactly what you want to do to prevent a constant from being changed.
2. Creates a new Scanner object called "in". Use this to read all values.