Modify the program you wrote for Programming Challenge 13 so it also calculates and displays the amount of money Package A customers would save if they purchased Package B or C, and the amount of money Package B customers would save if they purchased Package C. If there would be no savings, no message should be printed.

*/

import java.util.Scanner;

public class InternetServiceProviderPart2 {
   
    // hours is static because passing it between all of the functions isn't needed for a small program, such as this.
    static double hours;
   
    public static void main (String args[])
    {
        Scanner userInput = new Scanner (System.in);
       
        while (true)
        {
            // Calls printMonthlyBill with the appropriate functions as parameters, which executes them
            printMonthlyBill(calculateBill(getHours(userInput), menu(userInput)));
        }
    }
   
    // Gets hours
    public static double getHours(Scanner userInput)
    {    
        System.out.print("Please enter the hours used: ");
        hours = userInput.nextDouble();
       
        return hours;
    }
   
    // Displays main menu and gets user's package
    public static int menu (Scanner userInput)
    {
        int packageChoice;
       
        System.out.println("\n[1] Package A");
        System.out.println("[2] Package B");
        System.out.println("[3] Package C");
        System.out.print("Please select your package: ");
        packageChoice = userInput.nextInt();
       
        return packageChoice;
    }
   
    // Calculates the bill
    public static double calculateBill(double hours, int packageChoice)
    {
        switch (packageChoice)
        {
            case 1:
                return getPackageA(hours);
               
            case 2:
                return getPackageB(hours);
               
            case 3:
                return getPackageC();
               
            default:
                System.out.println("\nInvalid input!");
                return 0;
        }
    }
   
    // Prints bill and savings
    public static void printMonthlyBill(double bill)
    {    
        if (bill != 0)
        {
            System.out.printf("\nYour monthly bill is $%.2f\n", bill);
            getSavings(bill);
            System.out.printf("\n\n");
        }
       
        else
            System.out.println("\n");
    }
   
    // Gets bill if user has Package A
    public static double getPackageA(double hours)
    {    
        if (hours < 10)
        {
            return 9.95;
        }
       
        else
        {
            return (hours - 10)*2 + 9.95;
        }
    }
   
    // Gets bill if user has Package B
    public static double getPackageB(double hours)
    {    
        if (hours < 20)
        {
            return 13.95;
        }
       
        else
        {
            return (hours - 20) + 13.95;
        }
    }
   
    // Gets bill if user has Package C
    public static double getPackageC()
    {
        return 19.95;
    }
   
    // Checks if savings are applicable and displays potential savings to the user
    public static void getSavings(double bill)
    {
        if(bill > getPackageA(hours))
        {
            System.out.printf("If you had Package A, you'd save $%.2f\n", bill - getPackageA(hours));
        }
       
        if(bill > getPackageB(hours))
        {
            System.out.printf("If you had Package B, you'd save $%.2f\n", bill - getPackageB(hours));
        }
       
        if(bill > getPackageC())
        {
            System.out.printf("If you had Package C, you'd save $%.2f\n", bill - getPackageC());
        }
    }
}