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  1. #1
    New to the CF scene
    Join Date
    Feb 2012
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    Exclamation New to CF and new to Java! Please help!

    Hi all,

    I'm enrolled in a Java class and I'm having trouble with an array in a for loop.

    Here's the entire code:
    import java.text.DecimalFormat;
     * @author KenanCross
    public class MortgageCalcArray {
        int i; // counter
        int termLimit;
        int payments;
        double balPdCalc; //Calculated result of balPd and balPd2
        double loanCalc;   //Power of Calculation for compound interest
        double[] rates = {0.0525,0.055,0.0575}; //Array containing interest rates
        double[] results = new double[3]; //Array containing computed results
        int[] lengths = {7,15,30}; //Array containing values of corresponding years.
        double annualRate;  //Computed Annual Rate
        double interestPlus; // rate + 1
        double interestAdj;
        double interestExp;
        double principle; /* Principle loan amount */
        double monthlyPayment; /* Calculated Monthly Payment */
        DecimalFormat dec;
        DecimalFormat percentage;
    public static void main (String args[]){
    	MortgageCalcArray calc = new MortgageCalcArray();
    public MortgageCalcArray(){
    	principle = 200000;
    	dec = new DecimalFormat ("$0.00");
            percentage = new DecimalFormat("0.00%");
    public void calculatePaymentAmount(){
        for (i=0; i <= lengths.length; i++)
    	annualRate = (rates[i]/(12));
            payments = (12) * (lengths[i]);
    	interestAdj = (annualRate)+(1);
    	interestExp = Math.pow(interestAdj, payments);
    	results[i] = principle * (annualRate * interestExp)/(interestExp - 1);
    public void printPaymentAmount (){
         System.out.println("Your Loan Amount is "+ dec.format(principle));
         System.out.println("\t Your monthly payment at " + (lengths[0]) + " years, with a " + percentage.format (rates[0])  + " rate, is " + dec.format (results[0]));
    I'm trying to get the for loop to call the different values in the array in conjunction with each loop iteration from variable i, then store the results in the results array at the bottom.

    I keep getting a java.lang.ArrayIndexOutOfBoundsException: 3 throw error, yet I can't figure out where I went wrong.

    Any help you can give would be greatly appreciated!

  • #2
    God Emperor Fou-Lu's Avatar
    Join Date
    Sep 2002
    Saskatoon, Saskatchewan
    Thanked 2,662 Times in 2,631 Posts
    Java is 0 based. When you iterate up to a size using array.length, that would say you have 3 items within your array. These items are located at 0, 1, and 2. When you use <= it is moving from 0 through 3 inclusive, so its attempting to access a 4th element and tosses that error.

  • Users who have thanked Fou-Lu for this post:

    KenanCross (02-12-2012)

  • #3
    New to the CF scene
    Join Date
    Feb 2012
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    Thanks for your response! I was able to figure it out.


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