1. Sample Java Program

• 
  import java.util.Scanner;
  /*
   * Author:  J. Murach
   * Purpose: This program uses the console to get a subtotal 
   * from the user, and it calculates the discount amount and 
   * total and displays them.
  */
  public class InvoiceApp
  {
      public static void main(String[] args)
      {
          // display a welcome message
          System.out.println(
              "Welcome to the Invoice Total Calculator");
          System.out.println();  // print a blank line
  
          // get the input from the user
          Scanner sc = new Scanner(System.in);
          System.out.print("Enter subtotal:   ");
          double subtotal = sc.nextDouble();
  
          // calculate the discount amount and total
          double discountPercent = .2;
          double discountAmount = subtotal * discountPercent;
          double invoiceTotal = subtotal - discountAmount;
          // format and display the result
          String message = "Discount percent: " +  
              discountPercent + "\n" +
              "Discount amount:  " + discountAmount + "\n" +
              "Invoice total:    " + invoiceTotal + "\n";
          System.out.println(message);
      }//main
  }//class InvoiceApp