RetirementCalculator

import java.util.Scanner;

public class RetirementCalculator {

    public static void main(String[] args) {

        double averageInterest, amountInvested, endTotal;
        int yearsWait;

        Scanner keyboard = new Scanner(System.in);

        System.out.println("How much did you invest?");
        amountInvested = keyboard.nextDouble();

        while (amountInvested < 1) {
            System.out.println("Amount cannot be negative.");
            System.out.println("How much did you invest? ");
            amountInvested = keyboard.nextDouble();
        }

        System.out.println("How many years do you plan to wait before drawing from your account?");
        yearsWait = keyboard.nextInt();
        while (yearsWait < 1) {
            System.out.println("Years cannot be negative.");
            System.out.println("How many years do you plan to wait before drawing from your account?");
            yearsWait = keyboard.nextInt();
        }

        System.out.println("What is the average expected rate of interest?");
        averageInterest = keyboard.nextDouble();
        while (averageInterest < 0) {
            System.out.println("Average interest cannot be negative.");
            System.out.println("What is the average expected rate of interest?");
            averageInterest = keyboard.nextDouble();
        }

        endTotal = amountInvested * Math.pow((1 + averageInterest), yearsWait);

        System.out.printf("After waiting %,d years, your investment will yield $%,2f.", yearsWait
                , endTotal);
    }
}