Compound Interest Calculator

Question

hi, im trying to create a compound interest calculator which allows the input of the year you would like to calculate and the amount of money, the interest should already be configured into the code which is of a rate of 5.5 percent
import javax.swing.JOptionPane;
public class Savings
public static void main(String[] args) {
               String input;
               String years;
               double amount;
               double rate = 5.5;
               String input = JOptionPane.showInputDialog("Enter the amount of money");
               double principal = double.parseDouble(input);
               String years = JOptionPane.showInputDialog("Enter the amount of years");
               int nOfyears = int.parseInt(years);
               amount = principal(1+rate)*nOfyears;
               JOptionPane.showMessageDialog(amount);
This is basically what ive written so far but I know there are many mistakes, can someone help me correct it or tell me what I need to add or remove?
Thank you

Answer 1

jakal121 wrote:
OMG, thank you so much for that, it got rid of the problems I was having, I have updated the code now and some of the calculation process but Ive run into another problem, the following is the full updated code:
import javax.swing.JOptionPane;
import java.lang.Math;
public class Savings
     public static void main(String[] args) {
          String input;
          String years;
          double amount;
          double rate = 0.55;
               input = JOptionPane.showInputDialog("Enter the amount of money");
               double principal = Double.parseDouble(input);
               years = JOptionPane.showInputDialog("Enter the amount of years");
               double nOfyears = Double.parseDouble(years);
          amount = principal * Math.pow((1+rate), years);
JOptionPane.showMessageDialog(amount);
}the line which is causing an error is
amount = principal * Math.pow((1+rate), years);the error:
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - cannot find symbol
symbol:   variable principal
location: class Savings
at Savings.main(Savings.java:22)p.s thank you for the enormous amount of help georgemcYou're most welcome. I'm not going to fix your other problem for you, though. Instead I'm going to give you two very valuable bits of advice that I think are worth far more than me just correcting your code for you:
1) Next time you have a problem with your code, read, then try to interpret the error messages you get. Nothing else will speed up your productivity than this. They might seem cryptic at first, but they're really not, if you just take the time to think about it. Learn how to do this and you'll find that first of all you manage to fix these problems all on your own, and secondly, that you eventually stop making the mistakes at all. Persevere, trust me!
2) If you really can't figure out what's wrong, and really do need help, feel free to ask here. But make sure your first post explains clearly what the actual problem is. If you've got an error message, tell us what it is. Tell us where you think it's happening. Show a bit of code. Help us to help you, in fact. Makes everyone a happy panda
Good luck