C#的学习

     double balance, interestRate, targetBalance;
            Console.WriteLine("What's your current balance?");
            balance = Convert.ToDouble(Console.ReadLine());
            Console.WriteLine("What's your current annual interest rate (in %)?");
            interestRate = 1 + Convert.ToDouble(Console.ReadLine()) / 100.0;
            Console.WriteLine("what balance would you like you to have?");
            targetBalance = Convert.ToDouble(Console.ReadLine());
            int totalYears = 0;
            do
            {
                balance *= interestRate;
                ++totalYears;
            }
            while (balance < targetBalance);
            Console.WriteLine("In{0} year{1} you'll have a balance of {2}.",
            totalYears, totalYears == 1 ? "" : "a", balance);
            Console.ReadKey();