Thread: How to round to 2 decimal places in a dialog box

I know how to print using the printf method, but can't for the life of me get it to round to two decimal places using a dialog box.

import javax.swing.JOptionPane;
 
public class Program6 {
 
    public static void main(String[] args) {
        //declare variables
        double loanAmount, annualInterestRate, monthlyPayment, 
        monthlyInterestRate, monthlyInterest, totalPaid;
 
        int month;
 
 
//promt user to enter amount borrowed
        String loanAmountString = JOptionPane.showInputDialog
                (null, "Enter the amount to be borrowed in dollars");
        loanAmount = Double.parseDouble(loanAmountString);
 
        //prompt user to enter annual interest
        String annualInterestRateString = JOptionPane.showInputDialog 
                (null, "Enter the annual interest rate, eg 12 percent");
        annualInterestRate = Double.parseDouble(annualInterestRateString);
        annualInterestRate = (annualInterestRate / 100);
 
       //calculate monthly interest rate
        monthlyInterestRate = annualInterestRate / 12;
 
        //calculate monthly interest payment
        monthlyInterest = loanAmount * monthlyInterestRate;
 
        //display monthly interest
        JOptionPane.showMessageDialog(null, "The Monthly interest is " +
                monthlyInterest);
 
        //promt user to enter amount to be paid each month
        String monthlyPaymentString = JOptionPane.showInputDialog
                (null, "Enter the amount to be paid each month. "
                + "Amount must be greater than monthly interest.");
        monthlyPayment = Double.parseDouble(monthlyPaymentString);
 
 
 
        //parse double
        totalPaid = 0.00f;
        month = 0;
 
        //begin first loop
        while (monthlyPayment <= monthlyInterest) {
      String newMonthlyPaymentString = JOptionPane.showInputDialog
      (null, "Your payment does not cover the interest on your loan. "
              + "Please enter a larger amount for your monthly payment.");
      monthlyPayment = Double.parseDouble(newMonthlyPaymentString);
        }
 
        double loanAmountRemaining = loanAmount;
 
        //begin second loop
        while (loanAmount != 0) {
 
        totalPaid += monthlyPayment;
 
        monthlyInterest = loanAmountRemaining * monthlyInterestRate;
 
        loanAmount += monthlyInterest;
 
        loanAmountRemaining = (loanAmount - totalPaid);
 
        month++;
 
        if (monthlyPayment > (loanAmountRemaining))
        {
            totalPaid += loanAmountRemaining;
 
            loanAmount = 0;
 
            month++;
        }
        }
 
        //display message that loan has been paid
        String.format("%.2f", totalPaid);
        JOptionPane.showMessageDialog
(null,"Congradulations! You have paid off your loan. Total amount paid is $" 
                + totalPaid);
}
}

//display message that loan has been paid
String.format("%.2f", totalPaid);
JOptionPane.showMessageDialog
(null,"Congradulations! You have paid off your loan. Total amount paid is $"
+ totalPaid);
}
}
The last part is the part i want limited to 2 decimal places.

You aren't doing anything with the String returned by String.format("%.2f", totalPaid). Use it in the message you display.

(Notice that String.format() does return something. It does not alter totalPaid in any way.)