Join 300,492 Java Programmers for FREE! Get instant access to thousands of Java experts, tutorials, code snippets, and more! There are 1,833 people online right now. Registration is fast and FREE... Join Now!
The code compiles and runs. Monthly payment is correct for each loan. Problem is amortization numbers are wrong and each different loan seems to be wrong in a different way. Algorithms are the same for each. Also the scroll bars in the amortization area are not present and amortization does not refresh (change) when different loans are chosen.
I'm at a loss at this point. Please help.
CODE
/** * @(#)MortgageCalculatorServiceRequest5.java * * Week 3 Individual Assignment * * @version 1.00 2007/11/12 * * Write the program in Java (with a graphical user interface) and have it calculate * and display the mortgage payment amount from user input of the amount of the mortgage * and the user's selection from a menu of available mortgage loans:
- 7 years at 5.35% - 15 years at 5.5% - 30 years at 5.75%
* Use an array for the mortgage data for the different loans. * Display the mortgage payment amount followed by the loan balance * and interest paid for each payment over the term of the loan. * Allow the user to loop back and enter a new amount and make a new selection or quit. * Please insert comments in the program to document the program. */
public class MortgageCalculatorServiceRequest5a { public static void main (String[] args) { JFrame window = new MortCalcGUI(); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setVisible(true); } }
//Declare variables & loan array and initialize with values double InterestPaid,PrinciplePaid,Balance,monthlyPay,loanAmount; int[] loanTerm = {7,15,30}; // loan term for 7 years, 15 years, and 30 years double[] intRate = {5.35,5.50,5.75}; // interest rates for 7 years, 15 years, and 30 years double loanAmt = loanAmount;
public void actionPerformed (ActionEvent e) { //Perform actions based upon which button was pressed (provides looping function) if ("Calculate7".equals(e.getActionCommand())) { DecimalFormat decimalPlaces = new DecimalFormat("0.00"); NumberFormat currency = NumberFormat.getCurrencyInstance();
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public double CalculatePayment15 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[1]/100/12)) / (1 - Math.pow(1/(1 + (intRate[1]/100/12)),loanTerm[1]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } } public double CalculatePayment30 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[2]/100/12)) / (1 - Math.pow(1/(1 + (intRate[2]/100/12)),loanTerm[2]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public void ClearFields () { //Set all text fields to blank fieldPayment.setText (""); fieldLoanAmount.setText (""); areaAmortTable.setText (""); }
public MortCalcGUI () { //Set up and initialize buttons for GUI bCalc7 = new JButton ("7 Year, 5.35%"); bCalc7.setActionCommand ("Calculate7"); bCalc15 = new JButton ("15 Year, 5.50%"); bCalc15.setActionCommand ("Calculate15"); bCalc30 = new JButton ("30 Year, 5.75%"); bCalc30.setActionCommand ("Calculate30"); bClear = new JButton ("Clear All Fields"); bClear.setActionCommand ("Clear"); bExit = new JButton ("Exit Program"); bExit.setActionCommand ("Exit");
//Set up labels and field sizes for GUI labelTitle = new JLabel ("Welcome to the Mortgage Calculator V5.0"); labelInstructions = new JLabel ("Enter the amount of the loan and then choose the term/rate of the loan."); labelPayment = new JLabel ("Monthly Payment:"); labelLoanAmount = new JLabel ("Amount of Loan:"); fieldPayment = new JTextField ("", 12); fieldLoanAmount = new JTextField ("", 10); labelAmortTable = new JLabel ("Amortization Table"); areaAmortTable = new JTextArea (10, 300);
JScrollPane scrollPane = new JScrollPane (areaAmortTable, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//Set up listeners for each button bCalc7.addActionListener(this); bCalc15.addActionListener(this); bCalc30.addActionListener(this); bClear.addActionListener(this); bExit.addActionListener(this);
//Construct GUI and set layout JPanel mine = new JPanel(); mine.setLayout (null);
You had a few problems I have managed to iron out for you. Here is a list of things that were wrong...
1) You forgot to set your initial loanAmt to what was in the fieldloanAmount field. You had your balance set to loanAmount but you never set loanAmount. So at the beginning of each calculation (after where you append the header to your amortization table) I have set loanAmt with the field value.
2) During each part of the loop, you were also not resetting your loanAmt to the final balance. You had Balance = loanAmt; but you were not adjusting loanAmt after each iteration. I used loanAmt as the end result instead of balance and added it to the table, then balance will get set to loanAmt at the top of each iteration.
3) Your scrollpane... you setup your scrollpane and added the table just fine, but then you attempt to add the table AND the pane. Remember that when you add the table to the pane, it is now just the pane. It is a container. So add just the pane. I have added comments to show you that part in the GUI.
Other than that, all is moving in the right direction. You might want to consider refactoring some of your calculations into one function, it would reduce your code drastically. Just a future improvement tip.
Here is the finished code...
CODE
/** * @(#)MortgageCalculatorServiceRequest5.java * * Week 3 Individual Assignment * * @version 1.00 2007/11/12 * * Write the program in Java (with a graphical user interface) and have it calculate * and display the mortgage payment amount from user input of the amount of the mortgage * and the user's selection from a menu of available mortgage loans:
- 7 years at 5.35% - 15 years at 5.5% - 30 years at 5.75%
* Use an array for the mortgage data for the different loans. * Display the mortgage payment amount followed by the loan balance * and interest paid for each payment over the term of the loan. * Allow the user to loop back and enter a new amount and make a new selection or quit. * Please insert comments in the program to document the program. */
public class MortgageCalculatorServiceRequest5a { public static void main (String[] args) { JFrame window = new MortCalcGUI(); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setVisible(true); } }
//Declare variables & loan array and initialize with values double InterestPaid,PrinciplePaid,Balance,monthlyPay,loanAmount; int[] loanTerm = {7,15,30}; // loan term for 7 years, 15 years, and 30 years double[] intRate = {5.35,5.50,5.75}; // interest rates for 7 years, 15 years, and 30 years double loanAmt = loanAmount;
public void actionPerformed (ActionEvent e) { //Perform actions based upon which button was pressed (provides looping function) if ("Calculate7".equals(e.getActionCommand())) { DecimalFormat decimalPlaces = new DecimalFormat("0.00"); NumberFormat currency = NumberFormat.getCurrencyInstance();
// Need to set the loan amount to the value from the field first // You need to do this for each of your loan calculations for 7, 15, and 30 years. loanAmt = Double.parseDouble(fieldLoanAmount.getText());
for (int x = 1; x <=(loanTerm[0]*12); x++) //Loop through all monthly payments for each loan {
Balance=loanAmt; //Set Balance to Loan Amount
//Calculations on monthly payment
InterestPaid=(((intRate[0]/100.0)/12.0)*Balance); //Monthly Interest paid PrinciplePaid=(paymentAmount-InterestPaid); //Applied towards principle loanAmt=(Balance-PrinciplePaid); //loan balance after payment
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public double CalculatePayment15 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[1]/100/12)) / (1 - Math.pow(1/(1 + (intRate[1]/100/12)),loanTerm[1]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public double CalculatePayment30 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[2]/100/12)) / (1 - Math.pow(1/(1 + (intRate[2]/100/12)),loanTerm[2]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public void ClearFields () { //Set all text fields to blank fieldPayment.setText (""); fieldLoanAmount.setText (""); areaAmortTable.setText (""); }
public MortCalcGUI () { //Set up and initialize buttons for GUI bCalc7 = new JButton ("7 Year, 5.35%"); bCalc7.setActionCommand ("Calculate7"); bCalc15 = new JButton ("15 Year, 5.50%"); bCalc15.setActionCommand ("Calculate15"); bCalc30 = new JButton ("30 Year, 5.75%"); bCalc30.setActionCommand ("Calculate30"); bClear = new JButton ("Clear All Fields"); bClear.setActionCommand ("Clear"); bExit = new JButton ("Exit Program"); bExit.setActionCommand ("Exit");
//Set up labels and field sizes for GUI labelTitle = new JLabel ("Welcome to the Mortgage Calculator V5.0"); labelInstructions = new JLabel ("Enter the amount of the loan and then choose the term/rate of the loan.");
labelPayment = new JLabel ("Monthly Payment:"); labelLoanAmount = new JLabel ("Amount of Loan:"); fieldPayment = new JTextField ("", 12); fieldLoanAmount = new JTextField ("", 10); labelAmortTable = new JLabel ("Amortization Table"); areaAmortTable = new JTextArea (10, 300);
JScrollPane scrollPane = new JScrollPane (areaAmortTable, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//Set up listeners for each button bCalc7.addActionListener(this); bCalc15.addActionListener(this); bCalc30.addActionListener(this); bClear.addActionListener(this); bExit.addActionListener(this);
//Construct GUI and set layout JPanel mine = new JPanel(); mine.setLayout (null);
You had a few problems I have managed to iron out for you. Here is a list of things that were wrong...
1) You forgot to set your initial loanAmt to what was in the fieldloanAmount field. You had your balance set to loanAmount but you never set loanAmount. So at the beginning of each calculation (after where you append the header to your amortization table) I have set loanAmt with the field value.
2) During each part of the loop, you were also not resetting your loanAmt to the final balance. You had Balance = loanAmt; but you were not adjusting loanAmt after each iteration. I used loanAmt as the end result instead of balance and added it to the table, then balance will get set to loanAmt at the top of each iteration.
3) Your scrollpane... you setup your scrollpane and added the table just fine, but then you attempt to add the table AND the pane. Remember that when you add the table to the pane, it is now just the pane. It is a container. So add just the pane. I have added comments to show you that part in the GUI.
Other than that, all is moving in the right direction. You might want to consider refactoring some of your calculations into one function, it would reduce your code drastically. Just a future improvement tip.
Here is the finished code...
CODE
/** * @(#)MortgageCalculatorServiceRequest5.java * * Week 3 Individual Assignment * * @version 1.00 2007/11/12 * * Write the program in Java (with a graphical user interface) and have it calculate * and display the mortgage payment amount from user input of the amount of the mortgage * and the user's selection from a menu of available mortgage loans:
- 7 years at 5.35% - 15 years at 5.5% - 30 years at 5.75%
* Use an array for the mortgage data for the different loans. * Display the mortgage payment amount followed by the loan balance * and interest paid for each payment over the term of the loan. * Allow the user to loop back and enter a new amount and make a new selection or quit. * Please insert comments in the program to document the program. */
public class MortgageCalculatorServiceRequest5a { public static void main (String[] args) { JFrame window = new MortCalcGUI(); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setVisible(true); } }
//Declare variables & loan array and initialize with values double InterestPaid,PrinciplePaid,Balance,monthlyPay,loanAmount; int[] loanTerm = {7,15,30}; // loan term for 7 years, 15 years, and 30 years double[] intRate = {5.35,5.50,5.75}; // interest rates for 7 years, 15 years, and 30 years double loanAmt = loanAmount;
public void actionPerformed (ActionEvent e) { //Perform actions based upon which button was pressed (provides looping function) if ("Calculate7".equals(e.getActionCommand())) { DecimalFormat decimalPlaces = new DecimalFormat("0.00"); NumberFormat currency = NumberFormat.getCurrencyInstance();
// Need to set the loan amount to the value from the field first // You need to do this for each of your loan calculations for 7, 15, and 30 years. loanAmt = Double.parseDouble(fieldLoanAmount.getText());
for (int x = 1; x <=(loanTerm[0]*12); x++) //Loop through all monthly payments for each loan {
Balance=loanAmt; //Set Balance to Loan Amount
//Calculations on monthly payment
InterestPaid=(((intRate[0]/100.0)/12.0)*Balance); //Monthly Interest paid PrinciplePaid=(paymentAmount-InterestPaid); //Applied towards principle loanAmt=(Balance-PrinciplePaid); //loan balance after payment
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public double CalculatePayment15 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[1]/100/12)) / (1 - Math.pow(1/(1 + (intRate[1]/100/12)),loanTerm[1]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public double CalculatePayment30 () { //Check for valid numeric imput try { //Perform payment calculations if input is valid fieldPayment.setText (""); double Payment =(loanAmount() * (intRate[2]/100/12)) / (1 - Math.pow(1/(1 + (intRate[2]/100/12)),loanTerm[2]*12)); return Payment; }
catch (NumberFormatException event) { //Display error message if input is invalid JOptionPane.showMessageDialog(null, " Invalid Entry!\nPlease enter only numeric values!!", "ERROR", JOptionPane.ERROR_MESSAGE); return 0; } }
public void ClearFields () { //Set all text fields to blank fieldPayment.setText (""); fieldLoanAmount.setText (""); areaAmortTable.setText (""); }
public MortCalcGUI () { //Set up and initialize buttons for GUI bCalc7 = new JButton ("7 Year, 5.35%"); bCalc7.setActionCommand ("Calculate7"); bCalc15 = new JButton ("15 Year, 5.50%"); bCalc15.setActionCommand ("Calculate15"); bCalc30 = new JButton ("30 Year, 5.75%"); bCalc30.setActionCommand ("Calculate30"); bClear = new JButton ("Clear All Fields"); bClear.setActionCommand ("Clear"); bExit = new JButton ("Exit Program"); bExit.setActionCommand ("Exit");
//Set up labels and field sizes for GUI labelTitle = new JLabel ("Welcome to the Mortgage Calculator V5.0"); labelInstructions = new JLabel ("Enter the amount of the loan and then choose the term/rate of the loan.");
labelPayment = new JLabel ("Monthly Payment:"); labelLoanAmount = new JLabel ("Amount of Loan:"); fieldPayment = new JTextField ("", 12); fieldLoanAmount = new JTextField ("", 10); labelAmortTable = new JLabel ("Amortization Table"); areaAmortTable = new JTextArea (10, 300);
JScrollPane scrollPane = new JScrollPane (areaAmortTable, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//Set up listeners for each button bCalc7.addActionListener(this); bCalc15.addActionListener(this); bCalc30.addActionListener(this); bClear.addActionListener(this); bExit.addActionListener(this);
//Construct GUI and set layout JPanel mine = new JPanel(); mine.setLayout (null);
"At DIC we be mortgage calculating killer ninjas!"
Thank you for your help. I'll check out the changes you made and also the recommendations. I'm very new to this and quite confused most of the time. Thanks again.
Can you provide some code so we can take a look at where you might be going wrong? We are always willing to help those who need it but ask that you help us help you by presenting what you have going already. Thanks!
Forum Index:
Programming Help |
C and C++ |
VB6 |
Java |
VB.NET |
C# |
ASP.NET |
PHP |
ColdFusion |
Perl and Python |
Ruby |
Databases |
Other Languages |
Game Programming |
Mobile Development |
Software Development |
Computer Science |
Industry News |
Programming Tutorials |
C++ Tutorials |
Visual Basic Tutorials |
Java Tutorials |
VB.NET Tutorials |
C# Tutorials |
Linux Tutorials |
PHP Tutorials |
ColdFusion Tutorials |
Windows Tutorials |
HTML/JavaScript Tutorials |
CSS Tutorials |
Flash Tutorials |
Web Promotion Tutorials |
Graphic Design & Photoshop Tutorials |
Software Development Tutorials |
Database Tutorials |
Other Language Tutorials |
ASP.NET Tutorials |
Game Programming Tutorials |
WPF & Silverlight Tutorials |
| 
