Double Values Not Showing Calculated Values - double

Question

I'm trying to calculate the payment term for the user. I try to crunch the numbers and spit them out, but that's not happening for some reason. However, it displays perfectly fine when I explicitly assign the variables a value while declaring them.
public static void creditCardPaymentCalculator()
{
//User Input Variables
Scanner userInput = new Scanner(System.in);
//User's Input
double purchaseAmount, interestAmount = 0, minimumMonthlyPayment;
//Table Counters
int[] month = new int[12];
double payment = 0;
double monthlyInterest = 0;
double principal = 0;
double remainingBalance = 0;
double yearsOfPayment = 0;
int yearCounter = 1;
int monthCounter = 0;
//Initialize Variables
//-------------------------------------------------------------------------
//Initialize Month Array
for (int i = 0; i < 12; i++)
{
month[i] = (i + 1);
}
//-------------------------------------------------------------------------
//Welcome Message
System.out.println("\n\n\n\nCredit Card Payment Calculator\n\n");
//Get User Input
System.out.println("Enter Your Purchase Amount");
purchaseAmount = userInput.nextDouble();
System.out.println("Enter Interest Amount");
interestAmount = userInput.nextDouble();
System.out.println("Enter Minimum Monthly Payment");
minimumMonthlyPayment = userInput.nextDouble();
//Calculate Input For Chart (Not Working)
payment = minimumMonthlyPayment;
monthlyInterest = (((interestAmount / 100) * remainingBalance / yearsOfPayment) / 12);
principal = payment - monthlyInterest;
remainingBalance = remainingBalance - principal;
//Calculate Number Of Years For Payment
yearsOfPayment = (((interestAmount / 100) * remainingBalance) + remainingBalance) / minimumMonthlyPayment;
//Output
System.out.printf("\n Year: %d/%.0f", yearCounter, yearsOfPayment);
System.out.printf("\nMonth Payment Interest Principal Remaining Balance");
System.out.printf("\n%d %.2f %.2f %.2f %.2f", month[monthCounter], payment, monthlyInterest, principal, remainingBalance);
//Increment Counters
monthCounter++;
if (month[monthCounter] == 12)
{
yearCounter++;
//Reset monthCounter
monthCounter = 0;
}
//Line Spacing
System.out.printf("\n\n\n\n\n");
}