import java.util.Scanner;
import java.text.NumberFormat;

public class InvoiceApp
{
   public static voice main(String[] args)
   {
     // create a Scanner object and start while loop
     Scanner sc = new Scanner(System.in);
     String choice = "y";
     while (choice.equalsIgnoreCase("y"))
     {
       // get the input from the user
       System.out.print("Enter subtotal: ");
       double subtotal = sc.nextDouble();

       // calculate the results
       double discountPercent = 0.0;
       if (subtotal >= 100)
           discountPercent = .1;
       else 
           discountPercent = 0.0;
       double discountAmount = subtotal * discountPercent;
       double totalBeforeTax = subtotal - discountAmount;
       double salesTax = totalBeforeTax * .05;
       double total = totalBeforeTax + salesTax;
       
       // format and display the results
       NumberFormat currency = NumberFormat.getCurrencyInstance();
       NumberFormat percent = NumberFormat.getPercentInstance();
       
       String message = 
          "Discount percent: " + percent.format(discountPercent) + "\n"
       + "Discount amount:   " + currency.format(discountAmount) + "\n"
       + "Total before tax:  " + currency.format(totalBeforeTax) + "\n"
       + "Sales Tax:         " + currency.format(salesTax) + "\n"
       + "Invoice total:     " + currency.format(total)  + "\n";
       System.out.println(message);
     
       // see if the user wants to continue
       System.out.print("Continue (y/n): ");
       choice = sc.next();
       System.out.println();

     }

   }

}


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output:


Enter subtotal:    150.50
Discount percent:  10%
Discount amount:   $15.05
Total before tax:  $135.45
Sales tax:         $6.77
Invoice total:     $142.22

Continue? (y/n):   



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