import java.io$.*$; $//$ Needed for PrintWriter and IOException

import java.util.Scanner; $//$ Needed for Scanner class

$/**$

$*$ Chapter $5$

$*$ Programming Challenge $3$: Distance File

$*$ This program demonstrates the Distance class.

$*/$

public class ModifiedDistanceDemo

$\{$

public static void main$($String$[]$ args$)$

throws IOException

$\{$

String filename; $//$ File name

double speed; $//$ Vehicle's speed

int maxHours; $//$ Number of hours

int period; $//$ Counter for time periods

$//$ Create a Scanner object for keyboard input.

Scanner keyboard $=$ new Scanner$($System$.$in$)$;

$//$ Get the file name.

System.out.print$("$The distance report will be $"+$

"written to a file.

Enter the $"+$

"file name: $")$;

filename $=$ keyboard.nextLine$()$;

$//$ Open the file; use PrintWriter class; name the PrintWriter class object outfile.

$................................................$

$//$ Get the speed.

System.out.print$("$Enter the vehicle's speed: $")$;

speed $=$ keyboard.nextDouble$()$;

$//$ Validate the speed.

while $($speed $<0)$

$\{$

$...................$

$...................$

$\}$

$//$ Get the number of hours.

System.out.print$("$Enter the number of hours the $"+$

"vehicle was in motion: $")$;

maxHours $=$ keyboard.nextInt$()$;

$//$ Validate the hours.

while $($maxHours $<1)$

$\{$

$..........................$

$..........................$

$\}$

$//$ Write the table header.

outFile.println$("$Hour$\backslash$tDistance Traveled"$)$;

outFile.println$("----------------------------------")$;

$//$ Write the table of distances.

period $=1$;

while $($period $<=$ maxHours$)$

$\{$

$//$ Create a Distance object for this period.

Distance d $=$ new Distance$($speed$,$ period$)$;

$//$ Write the distance for this period.

$.............................$

$//$ Increment period.

period$++$;

$\}$

$//$ Close the file.

$..................$

$\}$

$\}$