I've written a small assignment where I've created a TimeDepositAccountand am creating a method to get the current balance, new balance after calculating the interest, and then a withdraw method. I'm stuck on printing the new balance to System.out since for some reason, I'm unable to get the new balance. Second, I want to use a local variable for the withdraw method since in our upcoming test we'll be tested on those, but we never did them in class so I'm unsure as how to go about that.
public class TimeDepositAccount {
//instance fields
private double currentBalance;
private double interestRate;
//Constructors
public TimeDepositAccount(){}
public TimeDepositAccount(double Balance1, double intRate){
currentBalance = Balance1;
interestRate = intRate;
}
//Methods
public double getcurrentBalance(){
return currentBalance;
}
public void newBalance(){
currentBalance = currentBalance * (1 + (interestRate/ 100) );
}
public double getintRate(){
return interestRate;
}
public String toString(){
return "TimeDepositAccount[ currentBalance = "+getcurrentBalance()+",
interestRate = "+getintRate()+"]";
}
public class TimeDepositAccountTester{
public static void main (String[] args){
TimeDepositAccount tda = new TimeDepositAccount(10,2);
double currentBalance = tda.getcurrentBalance();
System.out.println(currentBalance);
tda.newBalance();
System.out.print(currentBalance);
}
}
I wanted the output to first print 10.0, then 10.2, but instead I get 10.0 both times.
You would want to change your main method to the following:
public static void main (String[] args){
TimeDepositAccount tda = new TimeDepositAccount(10,2);
double currentBalance = tda.getcurrentBalance();
System.out.println(currentBalance);
tda.newBalance();
currentBalance = tda.getcurrentBalance();
System.out.print(currentBalance);
}
The variable currentBalance stores what the balance was when you defined it. Changing the balance of tda does not change the value of currentBalance. Thus, to update the value of currentBalance, you need to run currentBalance = tda.getcurrentBalance(); again.
Related
So currently, I'm struggling to make one particular program in eclipse for an assignment, while I am able to make most of the program, I seem to struggle with the no argument part of the program as well as bringing the pieces of the first class into the second for a brief moment. Here is my code for the first class
// Preparation of the input
import java.util.Scanner;
public class primarySetUp {
public static void main(String[] args) {
// Variable Declaration
double userBagNumber;
double userBagWeight;
// Create Scanner
Scanner input = new Scanner(System.in);
java.util.Date date = new java.util.Date();
// Opening Statement
System.out.println("Welcome to the Coffee Sales Simulation!");
// Get User Input
System.out.println("How heavy do you want the bags to be?");
userBagWeight = input.nextDouble();
System.out.println("How many bags do you want?");
userBagNumber = input.nextDouble();
// Get output
// Date
System.out.println("Todays date: ");
System.out.printf("%tB %<te, %<tY", date);
System.out.println(""); // spacer
// Original Inputs
System.out.printf("\nNumber of Bags: %3.0f", userBagNumber);
System.out.printf("\nWeight of Each Bag: %3.2f", userBagWeight);
System.out.print(" lbs");
// Calling of the Class
secondarySetUp mysecondarySetUp = new secondarySetUp(userBagWeight, userBagNumber);
// End Program
System.out.println("\nThank you for shopping with us!");
}
}
and here is my code for the second class, which is full of errors in this case.
public class secondarySetUp {
// Constants
static double pricePerPound = 5.99;
static double taxRate = 0.0725;
int singleBagger, pounderBagger;
public secondarySetUp(double userBagWeight, double userBagNumber) {
// A method named getTaxRate() that returns the tax rate.
System.out.printf("\nPrice per Pound: $%2.2f", getPrice());
System.out.printf("\nSales Tax: $%2.2f", getTaxRate());
System.out.print(" %");
System.out.printf("\nPrice of one bag weighing one pound: %3.2f", getSale());
}
// No argument pricing
public Sale() {
singleBagger = 1;
pounderBagger = 1;
}
// First constructor receiving No argument pricing
public Sale(int w, int n) {
singleBagger = w;
pounderBagger = n;
}
// Sale without tax
public double getSale() {
return userBagWeight * singleBagger * pounderBagger;
}
// Get Sale Tax
public double getSaleTax() {
return (getSale() * taxRate);
}
// Get total pricing
public double getTotalPrice() {
return (getSale() + getSaleTax());
}
public double getPrice() {
return pricePerPound;
}
public double getTaxRate() {
return taxRate * 100;
}
}
If you have any sort of fixes I could apply, please let me know; I am planning on adding the print statements for the rest of the arguments as well, but I'd like to get Sale() fixed up first.
I see a problem in getSale() where you are trying to use userBagWeight, but that variable doesn't exist outside the constructor parameters, which could create a lot of problems since other methods are calling on it. The constructor taking
double userBagWeight, double userBagNumber, yet it's not assigning them to any fields or doing anything with them.
I missed the part where you are treating Sale() as a constructor, but those are no constructors. The constructor is named after your class name.
public secondarySetUp(double userBagWeight, double userBagNumber)
change Sale() to secondarySetUp and you will be fine.
here how your class should be like :
public class secondarySetUp {
// Constants
static double pricePerPound = 5.99;
static double taxRate = 0.0725;
int singleBagger, pounderBagger;
double userBagWeight, userBagNumber;
public secondarySetUp(double userBagWeight, double userBagNumber) {
this.userBagWeight = userBagWeight;
this.userBagNumber = userBagNumber;
singleBagger = 1;
pounderBagger = 1;
// A method named getTaxRate() that returns the tax rate.
System.out.printf("\nPrice per Pound: $%2.2f", getPrice());
System.out.printf("\nSales Tax: $%2.2f", getTaxRate());
System.out.print(" %");
System.out.printf("\nPrice of one bag weighing one pound: %3.2f", getSale());
}
// First constructor receiving No argument pricing
public secondarySetUp(int w, int n) {
singleBagger = w;
pounderBagger = n;
}
// Sale without tax
public double getSale() {
return userBagWeight * singleBagger * pounderBagger;
}
// Get Sale Tax
public double getSaleTax() {
return (getSale() * taxRate);
}
// Get total pricing
public double getTotalPrice() {
return (getSale() + getSaleTax());
}
public double getPrice() {
return pricePerPound;
}
public double getTaxRate() {
return taxRate * 100;
}
}
this is a keyword to tell the program that we want to use the field "instance variable", if we have a method with parameter that have same name as a field name, then to tell them apart we tell the program this.fieldName to know which one we talking about.
I am getting an error that says: C:\Users\Jasmi\payroll\src\Payroll.java:68:38
java: variable grossPay might not have been initialized, but I am not sure how to fix it.
public class Payroll {
public String calculateGrossPay;
public String calculateNetPay;
private String name;
private int idNumber;
private double hourlyPayRate;
private double hoursworked;
Payroll(String nameGiven, int idNumbergiven) {
name = nameGiven;
idNumber = idNumbergiven;
hourlyPayRate = 7.15;
hoursworked = 0;
}
public String getName() {
return name;
}
public int getIDNumber() {
return idNumber;
}
public double getHourlyPayrate() {
return hourlyPayRate;
}
public double getHoursWorked() {
return hoursworked;
}
public void setName(String nameGiven) {
name = nameGiven;
}
public void setIDNumber(int idNumbergiven) {
idNumber = idNumbergiven;
}
public void setHourlyPayRate(double hourlypayrategiven) {
hourlyPayRate = hourlypayrategiven;
}
public void setHoursWorked(double hoursworkedgiven) {
hoursworked = hoursworkedgiven;
}
//gross pay plus overtime
public double calculateGrossPay() {
double overtime;
overtime = 0;
double grossPay;
if (hoursworked < 40) grossPay = hourlyPayRate * hoursworked;
else {
overtime = hoursworked - 40;
grossPay = (overtime * 1.5 * hourlyPayRate) + (40 * hourlyPayRate);
}
return grossPay;
}
//deductions
public double calculateNetPay() {
double netPay;
double grossPay;
double deduction = (.2579) * grossPay;
return netPay;
}
}
Here is the second document:
import javax.swing.JOptionPane;
public class PayrollClassTest {
public static void main(String[] args) {
String userInputString;
String userName;
int userId;
double userhourlyPayRate;
double userHoursworked;
userName = JOptionPane.showInputDialog("enter the name of this employee: ");
userInputString = JOptionPane.showInputDialog("Please enter employee ID: ");
userId = Integer.parseInt(userInputString);
userInputString = JOptionPane.showInputDialog("Please enter Hourly Pay Rate: ");
userhourlyPayRate = Double.parseDouble(userInputString);
userInputString = JOptionPane.showInputDialog("Enter the hours worked: ");
userHoursworked = Double.parseDouble(userInputString);
Payroll payroll1 = new Payroll(userName, userId);
payroll1.setHourlyPayRate(userhourlyPayRate);
payroll1.setHoursWorked(userHoursworked);
System.out.println(payroll1.getName() + " has a gross pay of " + payroll1.calculateGrossPay());
System.out.println(payroll1.getName() + " has a net pay of " + payroll1.calculateNetPay());
System.exit(0);
}
private static void calculateGrossPay() {
}
private static void calculateNetPay() {
}
}
I have tried to change deductions to be shown as this:
//deductions
public double calculateNetPay() {
double netPay = 0;
double grossPay = 0;
double deduction = (.2579) * grossPay;
return netPay;
}
}
It does work, but the results do not show the deductions:
Here is an example of the results:
Betty has a gross pay of 13000.0
Betty has a net pay of 0.0
Process finished with exit code 0
This is when I put name as Betty, gross pay as 100, and hours worked as 100. It shows the overtime correctly, but not the deductions.
Any help is greatly appreciated. thanks!
If my understanding of the code is correct then the following is where you are wrong for this piece of code.
public double calculateNetPay() {
double netPay = 0;
double grossPay = 0;
double deduction = (.2579) * grossPay;
return netPay;
}
First: netPay has no value assigned
This method will always return 0.
Reason : The netPay variable is declared and initialized to 0.
What you probably want to do before your return statement is perhaps;
netPay = grossPay - deduction;
I could be wrong in that logic, but I am definitely right when I say that you need to put some value to netPay before you return it.
Second: grossPay has no value assigned
In this method, you multiple .2579 with grossPay, but grossPay is 0 that you have now initialized.
You are assuming that the variable grossPay is shared for the two methods calculateGrossPay and calculateNetPay.
That is not true.
These are both two separate local variables that are declared separately in two different methods and have two different scopes.
You can read more about scope of java variables here:
variable docs from oracle
"in scope" meaning in java : StackOverflow question
My recommendation is to make grossPay a class variable instead of a method variable so that it could be shared between the two methods of the same class instance. (Assuming you are calling calculateGrossPay before calculateNetPay every time, so that grossPay can have the right value assigned to it.)
I'm new to understand Java, so forgive me for my ignorance. I have compiled the following code:
import java.lang.Math;
public class Main{
double initialBalance;
double interestRate;
double years;
public static final double periodsPerYear = 12;
//constructer
public Main(double balance, double interest, double life){
}
//methods
double getMonthlyPayment(){
return Math.round(initialBalance * ((interestRate/periodsPerYear)+((interestRate/periodsPerYear)/(Math.pow(1+(interestRate/periodsPerYear),periodsPerYear*years)-1)))*100.00)/100.00;
}
//main method
public static void main(String[] args){
double initialBalance = 10000;
double interestRate = 0.05;
double years = 2;
Main loan = new Main( initialBalance, interestRate, years );
System.out.println(initialBalance);
System.out.println(interestRate);
System.out.println(years);
System.out.println(loan.getMonthlyPayment());
}
}
The problem is the line "System.out.println(loan.getMonthlyPayment())" returns 0.0 when I need to to return 438.71. What am I doing wrong?
In your initialization of the object:
Main loan = new Main(initialBalance, interestRate, years);
this constructor is called:
public Main(double balance, double interest, double life){
}
but it doesn't do anything. It's empty. You need to set the instance variables in the constructor, like so:
public Main(double balance, double interest, double life){
this.initialBalance = balance;
this.interestRate = interest;
this.years = life;
}
I am new in Java, I am trying to make a program for a wallet the first method should return the wallet current money which it does,but the second one which is supposed to add money to the wallet and return the result of the addition keeps returning me the value I am giving to add(addmoney).
package wallet;
import java.util.Scanner;
public class Wallet {
double money;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
Wallet w = new Wallet();
Double money = input.nextDouble();
System.out.println(walletbalance(money));
Double addmoney = input.nextDouble();
System.out.println(w.moneyaddition(addmoney));
}
public static double walletbalance(double bal) {
return bal;
}
public double moneyaddition(double added) {
return money = added + money;
}
}
The observed behavior is result of a side-effect. That is, you expected moneyaddition to return the result of money+added and wonder why the function returned just the added value instead of the sum. There's nothing wrong with the function your looking at, but in the prior call to walletbalance you've never set the money member, so 0 + added makes added. You need to fix the setter for this property, then it works:
public static double walletbalance(double bal) {
money = bal;
return bal;
}
I would like someones expert opinion on both of my account class and the test account interest class. The issue I am facing is that the code from the test account interest class just multiplies on from the previous 12 month compute interest when it is supposed to be used only once.
The issue is in the
public double computeInterest(int n)
{
balance=balance*(Math.pow((1+rate),n/12));
return balance;
}
It is in this method of where the problem is that I should not use the balance but to use a variable that will store the answer but I did not understand the person that very clearly and he was very vague by only stating a variable should be used.
public class Account
{
private double balance; //STATE
private double interestRate; //STATE
private double rate;//STATE
public Account()
{
balance = 0;
interestRate = 0;
}
public Account(double amount, double interestRate)
{
balance = amount;
rate = interestRate;
}
public void deposit(double amount)
{
balance=balance+amount;
}
public void withdraw(double amount)
{
balance = balance - amount;
}
public void setInterest(double rate)
{
balance = balance + balance * rate;
//this.setInterst = setInterest;
//setInterest = InterestRate / 12;
}
public double computeInterest(int n)
{
balance=balance*(Math.pow((1+rate),n/12));
return balance;
}
public double getsetInterest()
{
return rate;
}
public double getBalance()
{
return balance;
}
public void close()
{
balance =0;
}
}
This is my test account interest class:
public class TestAccountInterest
{
public static void main (String[] args)
{
Account acc1 = new Account(100, 0.1);//0.10);
Account acc2 = new Account(133, 0.2); //0.20);
/*************************************
ACC1 ACCOUNT BELOW
*************************************/
//acc1.deposit(100);
//acc1.withdraw(100);
System.out.println(acc1.computeInterest(12));
// //acc1.computeInterest(12);
// System.out.println(acc1.computeInterest(24));
/**************************************
ACC2 ACCOUNT BELOW
**************************************/
acc2.withdraw(100);
acc2.deposit(100);
//acc2.computeInterest(24);
System.out.println(acc2.computeInterest(24));
}
}
This is the final output:
110.00000000000001
191.51999999999998
As you can see for the second one the figure is multiplied by the 12 month compute interest with the 24 month compute interest this stems from the method in the account class:
public double computeInterest(int n)
{
balance=balance*(Math.pow((1+rate),n/12));
return balance;
}
If I take out the balance it still causes and error so I confused on this particular part.
Code,
public double computeInterest(int n) {
balance = balance * (Math.pow((1 + rate), n / 12));
return balance;
}
should be changed to
public double computeInterest(int n) {
return balance * Math.pow(1 + rate, n / 12);
}
You shouldn't change balance field while computing interest. You might like to have a separate method to update balance where you do , balance = balance + computed_interest or something like that.
Also, I have remove unnecessary parenthesis. That was not an error but simply making your code less readable.