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Java Programming Help for 2 files with a controlling class

First java class is the primary one which invokes other classes. I will copy the code for the two files. I cannot compile this code and I do not know why.
When I had the program in one file it ran fine, but the instructor wants it in two files. Can someone explain to me what I am doing, or did incorrectly?
File 1:
public class Wk2ToddFoughty {
public static void main(String[] args) {
SalaryCalc FinalSalaryCalc = new SalaryCalc();
FinalSalaryCalc.SalaryCalc();
}
}
File 2:
import java.util.Scanner;
class SalaryCalc {
Scanner in = new Scanner(System.in);
System.out.println("Enter your annual sales: $");
double sales = in.nextDouble();
double salary = 35000.00;
double commission = (sales * .015);
double totalSalary = salary + sales;
System.out.println("Your Salary + Commission is: $" + totalSalary );
}

It might be easier to understand if you kept to Java naming conventions - also see inline comments
public class Wk2ToddFoughty {
public static void main(String[] args) {
SalaryCalc myCalc = new SalaryCalc(); // SalaryCalc - name of class
// myCalc - name of object
myCalc.doCalc(); // doCalc - name of method (missing from your class)
}
}
// edit this class to add missing method
public class SalaryCalc {
public void doCalc () {
Scanner in = new Scanner(System.in);
System.out.println("Enter your annual sales: $");
double sales = in.nextDouble();
double salary = 35000.00;
double commission = (sales * .015);
double totalSalary = salary + sales;
System.out.println("Your Salary + Commission is: $" + totalSalary );
}
}

Your second file doesn't define a method called SalaryCalc. You should also honor standard Java naming practices, and keep input/output logic outside of your business classes.
import java.util.Scanner;
public class Wk2ToddFoughty {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("Enter your annual sales: $");
SalaryCalc calc = new SalaryCalc(35000);
double totalSalary = calc.calcSalary(in.nextDouble());
System.out.println("Your Salary + Commission is: $" + totalSalary);
}
}
public class SalaryCalc {
private double salary;
public SalaryCalc(double salary) {
this.salary = salary;
}
public void calcSalary(double sales) {
double commission = sales * 0.015;
return salary + sales + commission;
}
}

Accessing a double from one method to another one

I am a big beginner in java and just need to know how to use this variable from one method to another as it is part of an assignment. please help.
public class parking {
public static void input(String args[]) {
int hoursParked = IO.getInt("(\\(\\ \n(-,-) How many hours were you parked?\no_(\")(\")");
double bill = hoursParked * 0.5 + 2;
}
public static void output(String args[]) {
System.out.println(" Parking");
System.out.println("$2 Fee plus $0.50 every hour!");
System.out.println("\nYour amount owed is $" + bill + "0");
}
}

In your code, bill is a local variable in input. You cannot refer to that variable from outside input.
If input and output are to be separate methods, then the usual thing would be to make them instance methods and to create a parking instance to use the methods. That lets you store bill as an instance variable (aka "instance field"). (Normally classes are initially capped, e.g. Parking, so I'll do that here.)
public class Parking {
private double bill;
public Parking() {
this.bill = 0.0;
}
public void input() {
int hoursParked = IO.getInt("(\\(\\ \n(-,-) How many hours were you parked?\no_(\")(\")");
this.bill = hoursParked * 0.5 + 2; // Or perhaps `+=`
}
public void output() {
System.out.println(" Parking");
System.out.println("$2 Fee plus $0.50 every hour!");
System.out.println("\nYour amount owed is $" + this.bill + "0");
}
}
(Java makes using the this. when referring to instance members optional. I always advocate using it, as above, to make it clear we're not using a local variable. Other opinions vary, saying it's unnecessary and verbose. It's a matter of style.)
Usage
Parking p = new Parking();
p.input(args);
p.output();
Alternately, return the value of bill from input and then pass it into output:
public class Parking {
public static double input() {
int hoursParked = IO.getInt("(\\(\\ \n(-,-) How many hours were you parked?\no_(\")(\")");
return hoursParked * 0.5 + 2;
}
public static void output(double bill) {
System.out.println(" Parking");
System.out.println("$2 Fee plus $0.50 every hour!");
System.out.println("\nYour amount owed is $" + bill + "0");
}
}
Usage:
double bill = parking.input(args);
parking.output(bill);
Side note: Since neither input nor output did anything with args, I've removed it above.

You can declare as class variables, then access it.
public class parking {
private double bill;
public void input(String args[]) {
int hoursParked = IO.getInt("(\\(\\ \n(-,-) How many hours were you parked?\no_(\")(\")");
bill = hoursParked * 0.5 + 2;
}
public void output(String args[]) {
System.out.println(" Parking");
System.out.println("$2 Fee plus $0.50 every hour!");
System.out.println("\nYour amount owed is $" + bill + "0");
}

why I'm unable to calculate amount of sale, and amount of sales tax?

public class Purchase
{
int invoiceNumber = 1234;
double salePrice = 10.00;
double SalesTax;
public void setInvoiceNumber(int invoice)
{
invoiceNumber = invoice;
}
public void setSalePrice(double saleAmount)
{
salePrice = saleAmount;
SalesTax = (saleAmount * .05);//when I'm compiling it's not calculating
}
public void displaySalePrice()
{
System.out.println("Your invoice number is:" + invoiceNumber + ".");
System.out.println("Your sale amount is: " + salePrice + ".");
System.out.println("Your sales tax is: " + SalesTax + ".");
}
}
Your invoice number is:1234.
Your sale amount is: 10.0.
Your sales tax is: 0.0.-------Problem area
----jGRASP wedge2: exit code for process is 0.
----jGRASP: operation complete.

This will work...
public class Purchase
{
int invoiceNumber = 1234;
double salePrice = 10.00;
double SalesTax = 0.0; // by default this is initialized to zero.
public void setInvoiceNumber(int invoice)
{
invoiceNumber = invoice;
}
public void setSalePrice(double saleAmount)
{
salePrice = saleAmount;
SalesTax = (saleAmount * .05);//when I'm compiling it's not calculating
}
public void displaySalePrice()
{
System.out.println("Your invoice number is:" + invoiceNumber + ".");
System.out.println("Your sale amount is: " + salePrice + ".");
System.out.println("Your sales tax is: " + SalesTax + ".");
}
public static void main(String args[])
{
setSalePrice(10.0); // sets SalesTax to (100.0 * .05)
displaySalePrice();
}
}
Note that there are some stylistic issues with this class.
"SalesTax" starts with an upper case letter, which is supposed to be reserved for class (and interface) names. The correct spelling is "salesTax".
It lacks a constructor.
Example Constructor:
public Purchase(int invoiceN, double salesP, doubles salesT) {
invoiceNum = invoiceN;
salesPrice = salesP;
salesTax = salesT;
}
A purchase is a thing that doesn't change once it is made. Its data members are variable (change-able), but they should be invariable (final or constant).
final int invoiceNumber; // These are set in the Constructor.
final double salePrice; // Once they are set, they don't change.
final double salesTax;
The class has setters (which set/change the variables), but it lacks getters (which retrieve the values of the variables without changing them). In general, variables should be declared "private" and "final" whenever possible. So if I wrote this class, I would have written it like this:
Revised example:
public class Purchase
{
private final int invoiceNumber;
private final double salePrice;
private final double salesTax;
// Constructor
public Purchase(int invoiceN, double salesP) {
invoiceNum = invoiceN;
salesPrice = salesP;
salesTax = salesPrice * .05; // The Constructor can figure this out.
}
public int getInvoiceNumber()
{
return this.invoiceNumber; // "this." is optional
}
public double getSalePrice()
{
return this.salePrice();
}
public double getSalesTax()
{
return this.salesTax;
}
public void displaySalePrice()
{
System.out.println("Your invoice number is:" + getInvoiceNumber() + ".");
System.out.println("Your sale amount is: " + getSalePrice() + ".");
System.out.println("Your sales tax is: " + getSalesTax() + ".");
}
public static void main(String args[])
{
Purchase shoesPurchase = new Purchase(1234, 10.00);
shoesPurchase.displaySalePrice();
}
}

You are never using the setSalePrice method, hence your SalesTax parameter is never being initialized. You could initialize it like so: double SalesTax = salePrice * 0.05;

You are never calling setSalePrice, so the sales tax never gets set
here's one way to correct this, though really you should probably call setSalePrice before calling displaySalePrice, rather than inside of it
public void displaySalePrice()
{
setSalePrice(salePrice);
System.out.println("Your invoice number is:" + invoiceNumber + ".");
System.out.println("Your sale amount is: " + salePrice + ".");
System.out.println("Your sales tax is: " + SalesTax + ".");
}

A recursive program to help calculate two values in Java

I need some help with a program for my programming class. It's a recursive program that takes a subtotal and a gratuity rate given by the user that outputs the full total and the gratuity cost. This is what I've got so far, and for some reason it just doesn't work:
import java.io.*;
import java.until.Scanner;
public class gratuity {
private double total;
private double subTotal;
private double gratRate;
private double newSubTotal;
private double newGratRate;
public static void main(String[] args) {
System.out.print("Enter the subtotal: ");
System.out.print("Enter the gratuity rate: ");
Scanner scan = new Scanner(System.in);
Scanner myScan = new Scanner(System.in);
double subtotal = scan.nextDouble();
double gratRate = myScan.nextDouble();
System.out.println("The Gratuity is: " + newSubtotal);
System.out.println("The Total is: " + Total);
}
public static double computeGratRate() {
double newGratRate = (gratRate/100);
return newGratRAte;
}
public static double computeNewSub() {
double newSubTotal - (subTotal * newGratRate);
return newSubTotal;
}
public static double computeTotal() {
double total = (newSubTotal + newGratRate);
return total;
}
}
If anyone would help me figure out how to fix it, I would be very grateful! Thank you!

A few things.
You are creating new variables called "subtotal" and "gratRate" in Main. These values override the member variables of the class.
Your problem won't compile anyway, because...
All your methods are static, which is OK, but these static methods are accessing non-static variables. Make all your member variables of this class static. (Or make everything outside of Main not static and then have "Main" be a stub to just create an instance of the gratuity class.
You need to import java.util.Scanner, not java.until.Scanner.
This line is a compiler error:
double newSubTotal - (subTotal * newGratRate);
I think you mean:
double newSubTotal = (subTotal * newGratRate);
That should be enough hints for now.... keep trying.

Did you mean:
import java.util.Scanner;
public class Gratuity {
private double subTotal;
private double gratRate;
public static void main(String[] args) {
Gratuity gratuity = new Gratuity();
System.out.print("Enter the subtotal: ");
Scanner scan = new Scanner(System.in);
gratuity.setSubTotal(scan.nextDouble());
System.out.print("Enter the gratuity rate: ");
Scanner myScan = new Scanner(System.in);
gratuity.setGratRate(myScan.nextDouble());
System.out.println("The new GratRate is: " + gratuity.getNewGratRate());
System.out.println("The New Sub is: " + gratuity.getNewSub());
System.out.println("The Total is: " + gratuity.getTotal());
}
public double getNewGratRate() {
return gratRate/100;
}
public double getNewSub() {
return getNewGratRate() * subTotal;
}
public double getTotal() {
return getNewSub() + getNewGratRate();
}
public double getSubTotal() {
return subTotal;
}
public void setSubTotal(double subTotal) {
this.subTotal = subTotal;
}
public double getGratRate() {
return gratRate;
}
public void setGratRate(double gratRate) {
this.gratRate = gratRate;
}
}

Java program not outputting correctly

I'm having a little bit of trouble with my code that I can't seem to figure out. Whenever I run this, it prints "Customer is null" instead of inserting their name. It also always calculates all tax as 0 (something wrong with my if statement?).
Is there any chance you guys can spot the issue? It seems as though everything else works correctly. (Wrote methods in Customer class, calling them in TestCustomer class, and the instructions are at the end of the post).
Thank you for anyone who takes the time to read this and attempt to help. Sorry for so much information, I just have no clue what is causing this, so I figured I'd include everything.
Customer class
import java.util.Scanner;
import javax.swing.JOptionPane;
public class Customer {
public static double taxRate = 0.00;
public static double saleRate = 0.00;
String customerName;
double listSaleAmount;
double saleDiscount = 0;
double netSaleAmount;
double taxAmount;
double saleTotal;
boolean taxable;
public double total;
public Customer (String customerName, boolean taxable) {
}
public void calculateTax () {
saleDiscount = listSaleAmount*(saleRate/100);
netSaleAmount = listSaleAmount-saleDiscount;
if (taxable = true){
taxAmount = netSaleAmount*(taxRate/100);
}
else{
taxAmount = 0;
}
saleTotal = netSaleAmount + taxAmount;
total += saleTotal;
}
public void printRecord () {
System.out.println("Customer is " + customerName);
System.out.println("Sale amount is $" + listSaleAmount);
System.out.println("Discount amount is $" + saleDiscount);
System.out.println("Net Sale Amount is $" + netSaleAmount);
System.out.println("Tax amount is $" + taxAmount);
System.out.println("Total Sale Amount is $" + saleTotal);
System.out.println(" ");
}
public static void changeTaxAmount () {
Scanner input = new Scanner(System.in);
double userTaxAmount = Double.parseDouble(JOptionPane.showInputDialog("What is the Tax Rate? (8.25 & 8.50 for testing)"));
taxRate = userTaxAmount;
}
public static void changeSaleRate () {
Scanner input = new Scanner(System.in);
double userSaleAmount = Double.parseDouble(JOptionPane.showInputDialog("What is the Sale Discount Rate? (0.00 & 7.50 for testing)"));
saleRate= userSaleAmount;
}
public static void printTaxRate() {
System.out.println("Tax Rate is " + taxRate + "%.");
}
public static void printSaleRate() {
System.out.println("The Sale Rate is " + saleRate + ".");
System.out.println(" ");
}
}
TestCustomer class
public class TestCustomer {
/**
* #param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Customer customer1 = new Customer("Annie Smith", true);
Customer customer2 = new Customer("Bob Wilson", false);
Customer.changeTaxAmount();
Customer.printTaxRate();
Customer.changeSaleRate();
Customer.printSaleRate();
customer1.listSaleAmount = 65.00;
customer2.listSaleAmount = 52.00;
customer1.calculateTax();
customer1.printRecord();
customer2.calculateTax();
customer2.printRecord();
Customer.changeTaxAmount();
Customer.printTaxRate();
Customer.changeSaleRate();
Customer.printSaleRate();
customer1.listSaleAmount = 84.00;
customer2.listSaleAmount = 105.00;
customer1.calculateTax();
customer1.printRecord();
customer2.calculateTax();
customer2.printRecord();
double total2 = customer1.total + customer2.total;
System.out.println("The total of all sales is $" + total2);
}
}
Assignment sheet (Not worrying about printing to a file right now, just want the main mechanics to work)
Also, thank you to those of you who helped me with my last question on this project. You helped a lot.

In your constructor
public Customer (String customerName, boolean taxable) {
}
You are passed in parameters, but you never assign them to your class fields.
try
public Customer (String customerName, boolean taxable) {
this.customerName = customerName;
this.taxable = taxable;
}

You have to define your constructor in customer class to set values of customerName and texable class level variables:
public Customer (String customerName, boolean taxable) {
this.customerName = customerName;
this.taxable = taxable;
}
Also, there seems to be problem with the below if condition:
if (taxable = true){
You should use == operator for comparing:
if (taxable == true) {
Actually, you don't need to compare it. Just use:
if (taxable) {

Your constructor in Customer class should assign the name and taxable value to Customer data member.
public Customer (String customerName, boolean taxable) {
this.customerName = customerName;
this.taxable = taxable;
}

Instead of using if (taxable = true), simply use if (taxable).