G U I ( I need to add a gui) please help

Question

I am trying to design an implement a GUI for this program. This program should let the user input the interest rate, principle, and period, and should accumalate value of interest.
* File: CDInterest.java
* Tamar Thompson
* Description: This application program illustrates the use of Java library
* classes to perform certain useful calculations.
* It uses the java.lang.Math class to calculate the principal of a
* Certificate of Deposit (CD) invested at a certain interest rate for a certain
* time period. It uses the java.text.NumberFormat class to format the numerical results
* which represent dollar amounts and percentages.
import java.io.*; // Import the Java I/O Classes
import java.text.NumberFormat; // For formatting as $nn.dd or n%
public class CDInterest {
private BufferedReader input = new BufferedReader // Handles console input
(new InputStreamReader(System.in));
private String inputString; // Stores the input
private double principal; // The CD's initial principal
private double rate; // CD's interest rate
private double years; // Number of years to maturity
private double cdAnnual; // Accumulated principal with annual compounding
private double cdDaily; // Accumulated principal with daily compounding
* convertStringTodouble() converts a String of the form "54.87" into
* its corresponding double value (54.87).
* @param s -- stores the string to be converted
* @return A double is returned
private double convertStringTodouble(String s) {
Double doubleObject = Double.valueOf(s) ;
return doubleObject.doubleValue();
* getInput() handles all the input required by the program. It inputs
* three Strings and converts each to a (double) number, storing them
* in instance variables (principal, rate, and years).
private void getInput() throws IOException {
// Prompt the user and get the input
System.out.println("This program compares daily and annual compounding for a CD.");
System.out.print(" Input the CD's initial principal, e.g. 1000.55 > ");
inputString = input.readLine();
principal = convertStringTodouble(inputString);
System.out.print(" Input the CD's interest rate, e.g. 6.5 > ");
inputString = input.readLine();
rate = (convertStringTodouble(inputString)) / 100.0;
System.out.print(" Input the number of years to maturity, e.g., 10.5 > ");
inputString = input.readLine();
years = convertStringTodouble(inputString);
} //getInput()
* calcAndReportResults() handles all the interest calculations and reports
* the program's results. Note the use of Math.pow() to calculate the CD's
* value, and the use of the NumberFormat.format() methods for making the output
* look pretty.
private void calcAndReportResult() {
// Calculate and output the result
NumberFormat dollars = NumberFormat.getCurrencyInstance(); // Set up formats
NumberFormat percent = NumberFormat.getPercentInstance();
percent.setMaximumFractionDigits(2);
cdAnnual = principal * Math.pow(1 + rate, years); // Calculate interest
cdDaily = principal * Math.pow(1 + rate/365, years*365);
// Print the results
System.out.println("The original principal is " + dollars.format(principal));
System.out.println("The resulting principal compounded daily at " +
percent.format(rate) + " is " + dollars.format(cdDaily));
System.out.println("The resulting principal compounded yearly at " +
percent.format(rate) + " is " + dollars.format(cdAnnual));
} // calcAndReportResult()
* main() creates an instance of the CDInterest object and then invokes
* its methods to calculate the interest for a CD using values input by
* the user.
public static void main( String args[] ) throws IOException {
CDInterest cd = new CDInterest();
cd.getInput();
cd.calcAndReportResult();
} // main()
} // Interest

Answer 1

Then you are going to have to do a lot of rewriting, because GUI programs don't actively "get" input. (At least they shouldn't.) They passively wait until somebody keys some input into a field or clicks on a button. Have you looked at the Swing tutorial?