import java.util.*;
import java.text.NumberFormat;


public class FutureValueExceptionApp
{
   public static void main(String[] args)
   {
     System.out.println("Welcome to the Future Value Calculator\n");
     Scanner sc = new Scanner(System.in);  
     
     String choice = "y";
     while (choice.equalsIgnoreCase("y")) 
     {
       double monthlyInvestment = 0.0;
       double interestRate = 0.0;
       int years = 0;
       try
       {
         System.out.print("Enter monthly investment: ");
         monthlyInvestment = sc.nextDouble();
         System.out.print("Enter yearly interest rate: ");  
         interestRate = sc.nextDouble();
         System.out.print("Enter number of years: ");
         years = sc.nextInt();         
       }
       catch(InputMismatchException e)
       {
         sc.next();  // discard the incorrectly entered number
         System.out.println("Error! Invalid number. Try again\n");
         continue;   // jump to the top of the loop
       }
  
       double monthlyInterestRate = interestRate/12/100;
       int months = years * 12;
       double futureValue = calculateFutureValue(monthlyInvestment, monthlyInterestRate, months);
       
       NumberFormat currency = NumberFormat.getCurrencyInstance();
       System.out.println("Future value:       " +  currency.format(futureValue) + "\n");
       
       System.out.print("Continue? (y/n): ");
       choice = sc.next();
       System.out.println();

     }
   }
   private static double calculateFutureValue(double monthlyInvestment, double monthlyInterestRate, int months)
   {
        double futureValue = 0;
        for (int i = 1; i <= months; i++)
             futureValue = (futureValue + monthlyInvestment) * (1 + monthlyInterestRate);

        return futureValue;
   }
}