static void Main(string[] args)
        {
            while (true)     //主要就是公式的运用和if else 的嵌套
            {
                string a, b = "";
                double c, d, e,s,q;
                double m = 6.55 / 100 / 12; double n = 4.05 / 100 / 12;
                int x;
                Console.WriteLine("请选择房贷类型（商业贷款or公积金贷款）:");
                a = Console.ReadLine();
              
                if (a == "商业贷款")
                {
                    Console.WriteLine("请输入贷款金额（元）：");
                    c = Convert.ToDouble(Console.ReadLine());
                    Console.WriteLine("请输入贷款期限（月）：");
                    d = Convert.ToDouble(Console.ReadLine());
                     q = c / d;
                    Console.WriteLine("请输入还款方式（等额本息or等额本金）：");
                    b = Console.ReadLine();
                    if (b == "等额本金")
                    {
                        Console.WriteLine("您的期次为（就是贷款后的第几个月）：");
                        x = Convert.ToInt32(Console.ReadLine());
                        s = (d + 1) * c * (m / 2);
                        e = c / d + (c - (x - 1) * q) * m;
                        Console.WriteLine("您本月还款金额为" + e + "元");
                        Console.WriteLine("您本月利息为" + (e - q) + "元");
                        Console.WriteLine("您的利息总和为" + s + "元");
                        Console.WriteLine("您的本利总和为" + (s + c) + "元");
                        Console.WriteLine("您的本月月供为" + e+ "元");
                        //Console.WriteLine("您的累计归还总额为"e1+e2+……ex + "元");
                        Console.WriteLine("您的期次为" + x);
                        Console.WriteLine("您本月的偿还本息为" + e + "元");
                        Console.WriteLine("您本月的偿还利息为" + (e - q) + "元");
                        Console.WriteLine("您迄今为止偿还的本金为" + (x * q) + "元");
                        Console.WriteLine("您迄今为止尚未偿还的本金为" + (c - x * q) + "元");
                        if (x == 1)
                        {
                            Console.WriteLine("这个月是您的最高月供月");
                        }
                        else
                        {
                            Console.WriteLine("这个月份并不是您的最高月供月");
                        }
                    }
                    else if (b == "等额本息")
                    {
                        Console.Write("待定");
                    }
                    else
                    {
                        Console.WriteLine("请输入正确的还款方式：");
                    }

}
                if (a == "公积金贷款")
                {
                    Console.WriteLine("请输入贷款金额（元）：");
                    c = Convert.ToDouble(Console.ReadLine());
                    Console.WriteLine("请输入贷款期限（月）：");
                    d = Convert.ToDouble(Console.ReadLine());
                    q = c / d;
                    Console.WriteLine("请输入还款方式（等额本息or等额本金）：");
                    b = Console.ReadLine();
                    if (b == "等额本金")
                    {
                        Console.WriteLine("您的期次为（就是贷款后的第几个月）：");
                        x = Convert.ToInt32(Console.ReadLine());
                        s = (d + 1) * c * (m / 2);
                        e = c/d + (c - (x - 1) * q) * n;

Console.WriteLine("您本月还款金额为" + e + "元");
                        Console.WriteLine("您本月利息为" + (e - q) + "元");
                        //Console.WriteLine("您的累计归还总额为"e1+e2+……ex + "元");
                        Console.WriteLine("您的利息总和为" +s +"元");
                        Console.WriteLine("您的本利总和为" + (s+c) + "元");
                        Console.WriteLine("您本月月供为" + e+ "元");
                        Console.WriteLine("您的期次为" + x);
                        Console.WriteLine("您本月的偿还本息为" + e+"元");
                        Console.WriteLine("您本月的偿还利息为" + (e - q) + "元");
                        Console.WriteLine("您迄今为止偿还的本金为" + (x * q) + "元");
                        Console.WriteLine("您迄今为止尚未偿还的本金为" + (c - x * q) + "元");
                        if (x == 1)
                        {
                            Console.WriteLine("这个月是您的最高月供月");
                        }
                        else
                        {
                            Console.WriteLine("这个月份并不是您的最高月供月");
                        }
                    }
                    else if (b == "等额本息")
                    {
                        Console.Write("待定");
                    }
                    else
                    {
                        Console.WriteLine("请输入正确的还款方式：");
                    }

}

Console.ReadLine();
            }