Java Newb

Hi, I just started a java class and I have this assignment and I'm
stumped... I realize the code is messy... but I just started... so go easy
on me :)

Java Problem
I am working on this assignment. The user enters a loan amount, number of
years to repay, and annual percentage rate. The project is supposed to
output a table for each month's payment information. I wrote the attached
code and it works well. However, there is a lot of extra code to try and
get around a formatting problem. The output prints out in columns... when
an amount is something like 32.50 it prints out as 32.5 and messes up my
columns... very fustrating. As you will see in the code, I have attempted
to take steps to prevent this. It works 95% of the time... however... it
sometimes doesn't add the 0... and it sometimes addes a zero to the end of a
number that should not have a zero at the end... for example... it
occassionally turns something like 29.65 into 29.650. this screws up my
columns further. Is there a way to force 2 decimal places in a java
program? Or is there a way to align columns other than putting spacer
strings inbetween data elements?



import javax.swing.JOp tionPane;

public class Loan {
public static void main(String[] args) {
double annualInterestR ate;
int numOfYears = 0;
double loanAmount = 0;
double monthlyPayment = 0;
double interest = 0;
double principal = 0;
double principalpay = 0;
double payments = 0;
String spacer1="";
String spacer2="";
String spacer3="";

String loanAmountStrin g = JOptionPane.sho wInputDialog(nu ll,
"Enter Loan Amount:","Loan Amount",JOption Pane.QUESTION_M ESSAGE);

loanAmount=
Double.parseDou ble(loanAmountS tring);

String numOfYearsStrin g = JOptionPane.sho wInputDialog(nu ll,
"Enter Number of Years:","Number of Years",
JOptionPane.QUE STION_MESSAGE);

numOfYears = Integer.parseIn t(numOfYearsStr ing);

String annualInterestR ateString = JOptionPane.sho wInputDialog(nu ll,
"Enter Annual Interest Rate:","Annual Interest Rate",
JOptionPane.QUE STION_MESSAGE);

annualInterestR ate =
Double.parseDou ble(annualInter estRateString);

principal=loanA mount;
payments=numOfY ears*12;
int mypayments=(int )payments;

String[][] TableList;
TableList=new String[mypayments+1][4];

TableList[0][0] = "Payment#";
TableList[0][1] = "Interest";
TableList[0][2] = "Principal" ;
TableList[0][3] = "Balance";

for(int i=1;i < mypayments+1; i++)
{
TableList[i][0]=String.valueOf (i);
}


String output=TableLis t[0][0] + " " + TableList[0][1] + " " +
TableList[0][2] + " " + TableList[0][3];

for(int i=1; i < mypayments+1; i++)
{
interest = (principal*(ann ualInterestRate/100))/12;
monthlyPayment = principal*((ann ualInterestRate/100)/12)/
(1-(Math.pow(1/(1+((annualInte restRate/100)/12)), payments)));
principalpay = monthlyPayment - interest;
principal = principal - principalpay;
monthlyPayment = (int) (monthlyPayment * 100) / 100.0;
double myinterest = (int)(interest * 100) / 100.0;
double myprincipal = (int)(principal * 100) / 100.0;
double myprincipalpay = (int)(principal pay * 100) / 100.0;
int testint=(int)(m yinterest*100);
int testprin=(int)( myprincipal*100 );
int testpay=(int)(m yprincipalpay*1 00);

TableList[i][1]=String.valueOf (myinterest);
TableList[i][2]=String.valueOf (myprincipalpay );
TableList[i][3]=String.valueOf (myprincipal);

if(testint % 10 == 0)
TableList[i][1]=TableList[i][1]+'0';
if(testprin % 10 == 0)
TableList[i][3]=TableList[i][3]+'0';
if(testpay % 10 == 0)
TableList[i][2]=TableList[i][2]+'0';
payments--;

spacer1="...... ...";
spacer2="...... ";
spacer3="...... ";

if(i > 9)
spacer1="...... ..";
if(i > 99)
spacer1="...... .";
if(interest>99. 99)
spacer2="....." ;
if(interest<10)
spacer2="...... .";
if(principalpay <10)
spacer3="...... ";

output = output + "\n\r" + TableList[i][0] +
spacer1 + TableList[i][1] +
spacer2 + TableList[i][2] +
spacer3 + TableList[i][3];


}


System.out.prin tln(output);




System.exit(0);
}
}