Banking interest Q

Question

Im trying to make a program that calculates the compound interest of an account with the principle,interest rate, and years. Im trying to do it with dialogs/ The program has the output the return on the invesment if the principle is left to accumulate.

Im stuck on the calculation part, please help

package firstAssignment;

import java.util.Scanner;

import javax.swing.JOptionPane;

public class thinkingQuestion {

public static void main(String[] args) {

//Banking program that asks user for the amount of money they wish to invest in a 
//compound interest account (principle), the interest rate (percent value) and the time frame (years).

    Scanner in= new Scanner(System.in);

    String principle, interestVal, years;
    int newPrinciple,newYears;
    double total;

        principle=JOptionPane.showInputDialog("How much money would you like to invest?");

        interestVal=JOptionPane.showInputDialog("What's the interest rate?");   

        years=JOptionPane.showInputDialog("How many years?");

        //convert from String to integer

        newPrinciple=Integer.parseInt(principle);
        newYears=Integer.parseInt(years);

        double newInterestVal=Integer.parseInt(interestVal);

        total=JOptionPane.PLAIN_MESSAGE(newPrinciple*Math.pow(1+ newInterestVal, newYears), newYears);

Answer 1

I deleted somo variables you don't need, I think the main problem is on java syntax for show messages. Here you could see a tutorial:

https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

import javax.swing.JOptionPane;

public class InterestBanking {

    public static void main(String[] args) {

        // Banking program that asks user for the amount of money they wish to
        // invest in a
        // compound interest account (principle), the interest rate (percent
        // value) and the time frame (years).

        String principle, interestVal, years;
        float newPrinciple, newYears;

        principle = JOptionPane.showInputDialog("How much money would you like to invest?");

        interestVal = JOptionPane.showInputDialog("What's the interest rate?");

        years = JOptionPane.showInputDialog("How many years?");

        // convert from String to integer

        newPrinciple = Float.parseFloat(principle);
        newYears = Float.parseFloat(years);

        double newInterestVal = Float.parseFloat(interestVal);

        //You could change your calculation here if this isn't the need formula
        double interest = newPrinciple * Math.pow(1 + newInterestVal, newYears);

        //you were assigning the result to a total variable. That's not neccesary
        JOptionPane.showMessageDialog(null, "Interest:" + NumberFormat.getCurrencyInstance(new Locale("en", "US")).format(interest) + " In years: " + newYears);
    }
}