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Thread: Need help please

  1. #1
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    Default Need help please

    I have about 4 hours of class time with Java and have an assignment due. I cant figure out how to fix my code. I know Im having issues with my print statements but I just dont understand it. Here is what I have and what is required: Calculate and display the monthly payment amount to fully amortize a $200,000.00 loan over a 30 year term at 5.75% interest. Please help.


    package mortgagecalculator;


    public class MortgageCalculator {
    public static void main(String[] args) {

    }

    double annualInterest = 5.75; //This is the annual interest rate
    double loanAmount = 200000; //This is the loan amount
    double loanLengthInYears = 30; //This is the length of the loan in years


    //Formuals bieng used are:
    double monthlyInterest = annualInterest / 100 /12;
    double loanLengthInMonths = loanLengthInYears * 12;

    double monthlyPayment = (loanAmount * monthlyInterest) / (1 - Math.pow((1 + monthlyInterest), loanLengthInYears));


    System.out.println("MortgageCalculator");
    System.out.println("Annual Interest: 5.75%");
    System.out.println("Loan Amount: $200,000");
    System.out.println("Loan Length: 30 years");
    System.out.println("Monthly Payment: " + currencyFormat.format(monthlyPayment));

  2. #2
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    Default Re: Need help please

    What is currencyFormat.format. Are they custom class and method? If they are you will need to post the code. I think what you are looking for is the String.format
    method. Take a look at this link: Java Platform SE 7 look at the format method.

    Hope it helps

  3. #3
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    Default Re: Need help please

    Would it make a difference if that last println statement was replaced like this:


    package mortgagecalculator;


    /**
    *
    * @author Johnny
    */
    public class MortgageCalculator {
    public static void main(String[] args) {

    }

    double annualInterest = 5.75; //This is the annual interest rate
    double loanAmount = 200000; //This is the loan amount
    double loanLengthInYears = 30; //This is the length of the loan in years


    //Formuals bieng used are:
    double monthlyInterest = annualInterest / 100 /12;
    double loanLengthInMonths = loanLengthInYears * 12;

    double monthlyPayment = (loanAmount * monthlyInterest) / (1 - Math.pow((1 + monthlyInterest), loanLengthInYears));


    System.out.println("MortgageCalculator");
    System.out.println("Annual Interest: 5.75%");
    System.out.println("Loan Amount: $200,000");
    System.out.println("Loan Length: 30 years");
    System.out.println(monthlyPayment);

  4. #4
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    Default Re: Need help please

    Quote Originally Posted by kprofgold View Post
    Would it make a difference if that last println statement was replaced like this:


    package mortgagecalculator;


    /**
    *
    * @author Johnny
    */
    public class MortgageCalculator {
    public static void main(String[] args) {

    }

    double annualInterest = 5.75; //This is the annual interest rate
    double loanAmount = 200000; //This is the loan amount
    double loanLengthInYears = 30; //This is the length of the loan in years


    //Formuals bieng used are:
    double monthlyInterest = annualInterest / 100 /12;
    double loanLengthInMonths = loanLengthInYears * 12;

    double monthlyPayment = (loanAmount * monthlyInterest) / (1 - Math.pow((1 + monthlyInterest), loanLengthInYears));


    System.out.println("MortgageCalculator");
    System.out.println("Annual Interest: 5.75%");
    System.out.println("Loan Amount: $200,000");
    System.out.println("Loan Length: 30 years");
    System.out.println(monthlyPayment);
    Does this program even compiling? If no, paste here the errors/exceptions.

  5. #5
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    Default Re: Need help please

    I get cannot find symbol, identifier expected, and illegal start of type errors

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    Default Re: Need help please

    Can you copy the errors and paste here?

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    Default Re: Need help please

    I think this is the error Im not very good at this sorry.

    Listening on javadebug
    Not able to submit breakpoint LineBreakpoint MortgageCalculator.java : 81, reason: The breakpoint is set outside of any class.
    Invalid LineBreakpoint MortgageCalculator.java : 81
    User program running
    User program finished

  8. #8
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    Default Re: Need help please

    Well, i don't know why aren't you trying to understand what i mean to say.
    Simply,
    double annualInterest = 5.75; //This is the annual interest rate
    double loanAmount = 200000; //This is the loan amount
    double loanLengthInYears = 30; //This is the length of the loan in years
     
     
    //Formuals bieng used are:
    double monthlyInterest = annualInterest / 100 /12;
    double loanLengthInMonths = loanLengthInYears * 12;
     
    double monthlyPayment = (loanAmount * monthlyInterest) / (1 - Math.pow((1 + monthlyInterest), loanLengthInYears));
     
     
    System.out.println("MortgageCalculator");
    System.out.println("Annual Interest: 5.75%");
    System.out.println("Loan Amount: $200,000");
    System.out.println("Loan Length: 30 years");
    System.out.println(monthlyPayment);
    paste this piece of code inside main() and then check the closing and opening braces.

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    Default Re: Need help please

    Ok thank you... I was closing the code before I had even inputted anything and I had to restart my NetBeans for the code to run. But now the calculation is off and I think it may be within the math. Here are my results:

    MortgageCalculator
    Annual Interest: 5.75%
    Loan Amount: $200,000
    Loan Length: 30 years
    -6214.908191559089 (I know this should a positive # lol)

  10. #10
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    Default Re: Need help please

    (1 - Math.pow((1 + monthlyInterest), loanLengthInYears))
    It's giving the negative value.
    Last edited by Mr.777; December 19th, 2011 at 12:58 AM.

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    Default Re: Need help please

    I still havnt been able to fix the math yet.... but I noticed I am also getting a gray line under my loanLengthInMonths...the error is not a known variable in the current context

  12. #12
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    Default Re: Need help please

    but I noticed I am also getting a gray line under my loanLengthInMonths
    It's not an error but it is coz the variable loanLengthInMonths is not being used anywhere after assigning value to it.

    Also, i don't know what you are supposed to do, might be the problem in your formulas.

  13. #13
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    Default Re: Need help please

    Here is what I am supposed to calculate: Calculate and display the monthly payment amount to fully amortize a $200,000.00 loan over a 30 year term at 5.75% interest. And thank you for all of your help.

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    Default Re: Need help please

    I think I just figured it out. Heres the code

    public class MortgageCalculator {


    public static void main(String[] args) {
    double annualInterest = 5.75; //This is the annual interest rate
    double loanAmount = 200000; //This is the loan amount
    double loanLengthInYears = 30; //This is the length of the loan in years


    //Formuals bieng used are:
    double monthlyInterest = annualInterest /100/12;
    double loanLengthInMonths = loanLengthInYears * 12;

    double monthlyPayment = (loanAmount * monthlyInterest) * (1 + Math.pow((1 - monthlyInterest), loanLengthInYears));


    System.out.println("MortgageCalculator");
    System.out.println("Annual Interest: 5.75%");
    System.out.println("Loan Amount: $200,000");
    System.out.println("Loan Length: 30 years");
    System.out.println(monthlyPayment);
    }
    }

  15. #15
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    Default Re: Need help please

    Good Luck.