DO WHERE基本程序设计结构

package chapter3.Retirement;

import java.util.Scanner;

public class Retirement {
    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);

        System.out.print("How much money do you need to retire? ");
        double goal = in.nextDouble();

        System.out.print("How much money will you contribute every year? ");
        double payment = in.nextDouble();

        System.out.print("Interest rate in %: ");
        double interestRate = in.nextDouble();

        double balance = 0;
        int years = 0;

        while(balance < goal)
        {
            balance += payment;
            double interest =balance * interestRate / 100;
            balance += interest;
            years++;
        }

        System.out.println("You can retire in "+years+" years.");
    }

}

package chapter3.Retirement2;

import java.util.Scanner;

public class Retirement2 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        System.out.print("How much money will you contribute every year? ");
        double payment = in.nextDouble();

        System.out.print("Interest rate in %: ");
        double interestRate = in.nextDouble();

        double balance = 0;
        int year = 0;

        String input;

        do
        {
            balance += payment;
            double interest = balance * interestRate / 100;
            balance += interest;

            year++;

            System.out.printf("After year %d, your balance is %,.2f%n",year,balance);

            System.out.print("Ready to retire?(Y/N) ");
            input = in.next();
        }
        while(input.equals("N"));
    }
}