Modify the Miles Per Gallon application

In this exercise, you'll modify an application that calculates miles per gallon

based on the miles driven and gallons of gas entered by a user so it displays

accurate results.

Test the application

Open the project named ch$03\_$ex$1\_$MPG that's in the ex$\_$starts directory.

Then, review the code for this project.

Run the application and test it with a range of values. Note that the miles per

gallon value sometimes has several decimal places.

Run the application and enter $400$ miles and $15\mathrm{.}8$ gallons. Note that the miles

per gallon value is $25\mathrm{.}31645569620253.$

Use the Math class for rounding

Use the round$()$ method of the Math class to round the miles per gallon value

to a whole number before displaying it$.$ To do that, you may need to perform

an explicit cast.

Run the application and enter $400$ miles and $15\mathrm{.}8$ gallons. Make sure the code

rounds the miles per gallon correctly by comparing it to the value in step $3.$

Adjust the code so it rounds the miles per gallon value to two decimal places.

Run the application and enter $400$ miles and $15\mathrm{.}8$ gallons. Make sure the code

rounds the miles per gallon correctly by comparing it to the value in step $3.$

Use the NumberFormat class for rounding

Modify the application so it uses the NumberFormat class to round the miles

per gallon value to three decimal places.

Run the application and enter $400$ miles and $15\mathrm{.}8$ gallons. Compare the miles

per gallon value to the value in step $3$ and note that it uses half$-$even rounding.

Adjust the code so it rounds the miles per gallon value to two decimal places.

Run the application and enter $400$ miles and $15\mathrm{.}8$ gallons. Compare the miles

per gallon value to the value in step $3$ and note that it uses half$-$even rounding.

$---------------------$

import java.util.Scanner;

public class MPGApp $\{$

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

System.out.println$("$Welcome to the Miles Per Gallon calculator"$)$;

System.out.println$()$; $//$ print a blank line

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

String input;

String choice $="$y$"$;

while $($choice$.$equalsIgnoreCase$("$y$"))\{$

System.out.print$("$Enter miles driven: $")$;

input $=$ sc$.$nextLine$()$;

double miles $=$ Double.parseDouble$($input$)$;

System.out.print$("$Enter gallons of gas used: $")$;

input $=$ sc$.$nextLine$()$;

double gallons $=$ Double.parseDouble$($input$)$;

double mpg $=$ miles$/$gallons;

System.out.println$("$Miles per gallon is $"+$ mpg $+".")$;

System.out.println$()$;

System.out.print$("$Calculate another MPG$?($y$/$n$)$: $")$;

choice $=$ sc$.$nextLine$()$;

System.out.println$()$;

$\}$

$\}$

$\}$