/* Write a program which will keep track of a loan as you pay it off month by month.
 * There will be a minimum amount to pay off each month but some months you may be
 * able to pay more.  The user will input the monthly amount until the loan is paid
 * in full.  */
 
 import java.util.Scanner;
 
 public class LoanPayoff
 {
 	public static void main(String[] args)
 	{
 		Scanner in = new Scanner(System.in);
 		System.out.print("How much was the original loan?  ");
 		double amount = in.nextDouble();					// the amount to pay off
 		System.out.print("How much is your interest rate on the loan (annual interest)?  ");
 		double rate = in.nextDouble();						// the interest rate applied per year, we divide this by 12 and add this to the amount each month for interest accrued
 		double minimum, thisMonth;							// minimum amount required to pay which is 5% of the total, and the amount the user is paying this month
 		int count = 0;										// count the number of months it takes to pay off the loan
 		double totalPay=0;									// the total amount paid, used to compute average monthly payments at the end
 		while(amount > 0)									// iterate until the loan is paid off
 		{
 			amount += amount * rate / 1200;					// add interest to the amount for the current month
 			System.out.printf("Current balance:  $%8.2f\n", amount);		// output current amount and minimum payment for the month
 			minimum = .05 * amount;
 			System.out.printf("Minimum payment:  $%8.2f\n", minimum);
 			System.out.print("How much are you paying this month?  ");
 			thisMonth = in.nextDouble();					// input the amount for the month and data verify that it is at least the minimum amount
			while(thisMonth < minimum) 
			{
				System.out.printf("That is not enough, you must pay at least $%8.2f, try again  ", minimum);
	 			thisMonth = in.nextDouble();				
			} 			
			if(thisMonth > amount) thisMonth = amount; 		// if they input a value larger than the remaining amount, we only accept the needed amount
			amount -= thisMonth;							// deduct the payment from the remaining amount
			count++;										// they've now made 1 more payment, add 1 to count and add this payment to their total payment
			totalPay += thisMonth;
 		}
 		double average = 0;
 		if(count > 0) average = totalPay/count; 			// using the if to avoid a possible division by 0 error if there were no payments made
 		System.out.printf("Including interest, you paid $%8.2f over %d months averaging $%8.2f per month", totalPay, count, average);
 	}
 }