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Absolute java beginner. I cannot use a returned variable

This assignment is to calculate the cost of a hospital visit. I am trying to ask the user what the prices for the "overnightCharge", "medicationCharge", and "labCharge" are. I then try to use the input to add them together in the method called "total". Next, I try to print the resulting/returned variable from "total" method in the main method by typing System.out.println("Your total charge is: " + total(totalCost). I thought total(totalCost) would retrieve the variable returned by "total" method.
package hospitalstay;
import java.util.Scanner;
/* total charges
if overnight charges
medication charges
lab charges
ask user if new patient*/
public class HospitalStay {
public static void main(String[] args) {
System.out.println("Your total charge is: " + total(totalCost); // i want to print the "totalCost variable" returned by the "total" method.
}
public static double overnightCharge () {// asking user for overnight charge
Scanner sc = new Scanner (System.in);
System.out.println("What is your overnight charge");
double overnightCharge;
overnightCharge = sc.nextDouble();
return overnightCharge;
}
public static double medicationCharge() {// asking user for medication charge
Scanner sc = new Scanner (System.in);
System.out.println("What is your medication charge");
double medicationCharge;
medicationCharge = sc.nextDouble();
return medicationCharge;
}
public static double labCharge() {//asking user for lab charge
Scanner sc = new Scanner (System.in);
System.out.println("What is your lab charge");
double labCharge;
labCharge = sc.nextDouble();
return labCharge;
}
public static double total (double medicineCharge, double labCharge, double overnightCharge) {
double totalCost;
if (overnightCharge == 0) {
totalCost = (overnightCharge + medicineCharge + labCharge); //Calculating all three charges
}
else {
totalCost = (medicineCharge + labCharge);
}
return totalCost;
}
}

You have changeв the total method to
public static double total () {
return overnightCharge() + medicineCharge() + labCharge();
}
Also change main method to
public static void main(String[] args) {
System.out.println("Your total charge is: " + total());
}

First of all, you've defined three parameters for method "total," but you are specifying only one argument in your main method:
total(totalCost)
to minimize the number of things that you need to change in your code, I would simply change the total() method to:
public static double total() {
double totalCost = overnightCharge();
totalCost += medicationCharge();
totalCost += labCharge();
return totalCost;
}
and in your main method:
public static void main(String[] args) {
System.out.println("Your total charge is: " + total();
}

You are passing the wrong inputs to total, change your main to
public static void main(String[] args) {
System.out.println("Your total charge is: " + total(medicationCharge(), labCharge(), overnightCharge()));
}
Also, in your total method, you don't need the if condition, so you can simplify it to:
public static double total(double medicineCharge, double labCharge, double overnightCharge) {
return (overnightCharge + medicineCharge + labCharge);
}

"Explanation why your code didn't work as desired: "
You have created a function total() which takes 3 arguments i.e (double medicineCharge, double labCharge, double overnightCharge)
public static double total (double medicineCharge, double labCharge, double overnightCharge) {
return totalCost;
}
But when you are calling this function in your main() you are only passing it a single argument that is total(totalCost).
public static void main(String[] args) {
System.out.println("Your total charge is: " + total(totalCost); // i want to print the "totalCost variable" returned by the "total" method.
}
You have also made a typo mistake "medicineCharge"
You can try something like this to achieve your desired output :
import java.util.Scanner;
public class Hospital {
static Scanner input;
private static double overnightCharge, medicationCharge, labCharge,
totalCost;
public static double takeInput() { // single function to take input
input = new Scanner(System.in);
return input.nextDouble();
}
public static double overnightCharge() {// asking user for overnight charge
System.out.println("What is your overnight charge");
overnightCharge = takeInput();
return overnightCharge;
}
public static double medicationCharge() {// asking user for medication
// charge
System.out.println("What is your medication charge");
medicationCharge = takeInput();
return medicationCharge;
}
public static double labCharge() {// asking user for lab charge
System.out.println("What is your lab charge");
labCharge = takeInput();
return labCharge;
}
public static double total() {
overnightCharge();
medicationCharge();
labCharge();
if (overnightCharge == 0) {
totalCost = (overnightCharge + medicationCharge + labCharge); // Calculating
// all
// three
// charges only when overnightCharge = 0
} else {
totalCost = (medicationCharge + labCharge);
}
return totalCost;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("Total :" + total());
}
}
Note: I have also reduced the code for calling scanner again again.

How do I use the return value from a method in another method different from the calling method?

I'm kinda new to to java and stumbled on a problem that needs me to do currency conversion declaring different methods for:
getting amount, getting conversion rate, doing the actual conversion and printing the outcome of the conversion
import java.util.*;
public class Conver {
public static void main(String[] args){
amountToConvert();
exchangeRate();
convert();
}
public static double amountToConvert() {
Scanner input = new Scanner(System.in);
System.out.println("Enter the amount you wish to convert...");
double amount = input.nextDouble();
return amount;
}
public static double exchangeRate(){
Scanner input = new Scanner(System.in);
System.out.println("Enter the currency you wish to convert from... ");
String initialCurrency = input.next();
System.out.println("Enter the currency you wish to convert from... ");
String finalCurrency = input.next();
System.out.println("How many " + initialCurrency + " makes one " + finalCurrency + "?");
double rate = input.nextDouble();
return rate;
}
public static double convert(){
int x = amount*rate;
return x;
}
public void printResult(){
System.out.println(x);
}
}

Learn to use parameters in the methods. Change the convert() method so that it looks like this:
public static double convert(double amount, double rate){
int x = amount*rate;
return x;
}
In the method above, double amount and double rate are the parameters. Use variables to help pass in parameters to convert() in the main method:
public static void main(String[] args){
double amount1 = amountToConvert();
double rate1 = exchangeRate();
double result = convert(amount1, rate1);
printResult(result);
}
Hope this helps!

Pass returned values to the method convert:
import java.util.*;
public class Conver {
public static void main(String[] args){
double amount = amountToConvert();
double rate = exchangeRate();
double result = convert(amount, rate);
printResult(result);
}
public static double amountToConvert() {
Scanner input = new Scanner(System.in);
System.out.println("Enter the amount you wish to convert...");
double amount = input.nextDouble();
return amount;
}
public static double exchangeRate(){
Scanner input = new Scanner(System.in);
System.out.println("Enter the currency you wish to convert from... ");
String initialCurrency = input.next();
System.out.println("Enter the currency you wish to convert from... ");
String finalCurrency = input.next();
System.out.println("How many " + initialCurrency + " makes one " + finalCurrency + "?");
double rate = input.nextDouble();
return rate;
}
public static double convert(double amount, double rate){
double x = amount * rate;
return x;
}
public void printResult(double x){
System.out.println(x);
}
}
Also, don't use double for money!

First off, you need to change the "receiving method" so that it takes an argument. A method like:
public static double convert() {}
that needs to take in a value for amount and rate, needs to have those added to the method signature:
public static double convert (double amount, double rate) {}
Putting the two comma separated values inside of the parens means that this method takes two values, doubles, as arguments. This makes those values available to use inside of that method.
Now that you have a method that can take the required arguments, you need to actually use that method in your code. When calling this method, you start out the same as with others:
convert(
but then you need to add in the arguments you are using:
double amount = amountToConvert();
double rate = exchangeRate();
convert(rate, amount);
If you want to avoid creating those two additional variables in main(), you can actually call those methods inside of your new method:
convert(amountToConvert(), exchangeRate());

Java - Output not printing?

I'm a beginner to Java, and I'm trying to write a simple Java program that calculates an amount in a savings account based on an initial amount deposited, number of years, and an interest rate. This is my code, which compiles, but does not actually print the amount of money in the account (basically, it completely ignores my second method).
import java.util.*;
class BankAccount {
public static Scanner input = new Scanner(System.in);
public static double dollars;
public static double years;
public static double annualRate;
public static double amountInAcc;
public static void main(String[] args) {
System.out.println("Enter the number of dollars.");
dollars = input.nextDouble();
System.out.println("Enter the number of years.");
years = input.nextDouble();
System.out.println("Enter the annual interest rate.");
annualRate= input.nextDouble();
}
public static void getDouble() {
amountInAcc = (dollars * Math.pow((1 + annualRate), years));
System.out.println("The amount of money in the account is " + amountInAcc);
}
}
I think it is because I don't call the method anywhere, but I'm a bit confused as to how/where I would do that.

Call it once you have received all the required inputs from the Scanner.
// In main
System.out.println("Enter the number of dollars.");
dollars = input.nextDouble();
System.out.println("Enter the number of years.");
years = input.nextDouble();
System.out.println("Enter the annual interest rate.");
annualRate= input.nextDouble();
getDouble(); // Print out the account amount.

The main method is pretty much the entry point for the program to run. To call a static method in java you can just go:
public static void main(String[] args) {
...
BankAccount.getDouble();
...
}
If it wasn't static you have to create an instance of the class. like:
BankAccount account = new BankAccount();
account.getDouble();

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;
}
}

How to call method to main method (Program runs but does not print out questions) (Homework)

Response to previous program, Simply placing new balance(); where public static void main is, does not work, and without that the program runs but nerver prints out the user questions!
import java.io.*;
public class cInterest {
public static void main(String[] args) throws IOException
{
//new balance ;
}
public static double balance(double principal, double rate, double years) throws IOException{
double amount = 0;
String input;
BufferedReader myInput = new BufferedReader (new InputStreamReader (System.in));
System.out.print("How much would you like to take out? ");
input = myInput.readLine ();
principal = Double.parseDouble (input);
System.out.print("Enter the interest rate: ");
input = myInput.readLine ();
rate = Double.parseDouble (input);
for (int i = 1; i < years; i++) {
amount = principal * rate * years;
amount += principal;
}
return amount; //- principal;
}
}

balance is a method, not a class, so you can't use the new keyword. You want to call the method, instead, like this:
public static void main(String[] args) throws IOException
{
double balance = balance(0.0, 0.0, 1.0); // Awkward hard-coded variables! Ew!
System.out.println(balance);
}
But why are you passing these variables to the method when the user's just going to overwrite them? Your balance method should only be responsible for calculating the balance, not gathering user input. You can do that in the main method:
public static void main(String[] args) throws IOException
{
// Gather user input.
String input;
BufferedReader myInput = new BufferedReader (new InputStreamReader (System.in));
System.out.print("How much would you like to take out? ");
input = myInput.readLine ();
double principal = Double.parseDouble (input);
System.out.print("Enter the interest rate: ");
input = myInput.readLine ();
double rate = Double.parseDouble (input);
System.out.print("Enter the number of years: ");
input = myInput.readLine ();
double years = Double.parseDouble (input);
// Now do the calculations...
double balance = balance(principal, rate, years); // Much clearer!
System.out.println(balance);
}
public static double balance(double principal, double rate, double years) {
// Calculate the end balance based on the parameters, and return it.
}
Even better would be to put the gathering of user input into a dedicated method of its own, but I'm far enough off-topic as it is.

You should explicitly call the balance() method somewhere.

Use System.out.println instead of System.out.print, otherwise, your Stream will not be flushed. You can refer to the PrintStream javadoc for more informations.