房贷计算器代码2.0

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using System.Reflection;
using System.Net.NetworkInformation;

namespace play
{
    class Program
    {
        //短期利率与长期利率
        double lowRate = 0;
        double highRate = 0;

        //KeyValuePair<DateTime, >;
        DateTime dt1 = new DateTime(2015, 3, 1);
        DateTime dt2 = new DateTime(2015, 5, 11);
        DateTime dt3 = new DateTime(2015, 6, 28);
        DateTime dt4 = new DateTime(2015, 8, 26);
        //贷款金额
        static double totalMoney, balance;

        static string choice;
        static string newChoice;
        //期数
        int n;
        //月供
        double payMonth;
        double rate;
        double interest;
        /// <summary>
        /// 用来构建欢迎界面
        /// </summary>
        void Paint()
        {
            Console.WriteLine("***************************");
            Console.WriteLine("***************************");
            Console.WriteLine("***************************");
            Console.WriteLine("欢迎使用房贷计算器");
            Console.WriteLine("***************************");
            Console.WriteLine("***************************");
            Console.WriteLine("***************************");

            Console.WriteLine("请按任意键继续");
            Console.ReadKey();
            Console.Clear();
        }
        /// <summary>
        /// 按日期选择利率
        /// </summary>
        /// <param name="dt">输入的日期</param>
        void RateChoose(DateTime dt)
        {
            if (dt >= dt4)
            {
                lowRate = 0.0275;
                highRate = 0.0325;
            }
            else if (dt >= dt3)
            {
                lowRate = 0.03;
                highRate = 0.035;
            }
            else if (dt >= dt2)
            {
                lowRate = 0.0325;
                highRate = 0.0375;
            }
            else if (dt >= dt1)
            {
                lowRate = 0.035;
                highRate = 0.04;
            }
            else
            {
                Console.WriteLine("你输入的日期不在范围内");
                Console.ReadKey();
                Environment.Exit(0);
            }
        }
        /// <summary>
        /// 计算月供
        /// </summary>
        void Payment(DateTime dt)
        {
            //设置缓冲区高度，即设置显示的最大行数
            Console.BufferHeight = 1000;
            RateChoose(dt);
            switch (choice)
            {
                case "1":
                    {
                        //等额本息，月供计算方法
                        for (n = 1; n <= 360; n++)
                        {


                            if (n <= 60)
                            {
                                rate = lowRate;
                            }
                            else
                            {
                                rate = highRate;
                            }
                            //计算月供
                            double p;
                            p = rate / 12;
                            payMonth = (p * totalMoney * Math.Pow((1 + p), n)) / ((Math.Pow(1 + p, n) - 1));
                            //利息
                            interest = n * payMonth;
                            if (n % 2 == 0)
                            {
                                Console.ForegroundColor = ConsoleColor.Blue;
                            }
                            else
                            {
                                Console.ForegroundColor = ConsoleColor.White;
                            }
                            Console.WriteLine("{0}期按揭贷款的月供是{1:0.00}元，总利息是{2:0.00}元", n, payMonth, interest);

                        }
                    }
                    break;
                case "2":
                    {
                        //等额本金，月供计算方法
                        for (n = 1; n <= 360; n++)
                        {
                            if (n <= 60)
                            {
                                rate = lowRate;
                            }
                            else
                            {
                                rate = highRate;
                            }
                            //计算月供
                            double p;
                            p = rate / 12;
                            payMonth = (totalMoney / n) + totalMoney * p;
                            interest = ((totalMoney / n + totalMoney * p) + totalMoney / n * (1 + p)) / 2 * n - totalMoney;
                            Console.WriteLine("{0}期按揭贷款的首月还款额是{1:0.00}元,总利息是{2:0.00}元", n, payMonth, interest);
                        }
                    }
                    break;
            }
        }

        /// <summary>
        /// 月贷计算方法
        /// </summary>
        /// <param name="n">还款期数</param>
        void Compute(int n)
        {
            Console.WriteLine("期次		偿还利息		偿还本金		还款额		剩余本金");
            switch (choice)
            {

                case "1":
                    //等额本息法计算房贷
                    {
                        if (n <= 60)
                        {
                            rate = lowRate;
                        }
                        else
                        {
                            rate = highRate;
                        }

                        double p;
                        p = rate / 12;
                        payMonth = (p * totalMoney * Math.Pow((1 + p), n)) / ((Math.Pow(1 + p, n) - 1));
                        for (int i = 1; i <= n; i++)
                        {
                            //string s = i.ToString();
                            interest = totalMoney * p;
                            double capital = payMonth - interest;
                            totalMoney -= capital;
                            Console.WriteLine("{0}		{1:0.00}		{2:0.00}	{3:0.00}	{4:0.00}", i, interest, capital, payMonth, totalMoney);
                        }
                    }
                    break;
                case "2":
                    //等额本金法计算房贷
                    {
                        if (n <= 60)
                        {
                            rate = lowRate;
                        }
                        else
                        {
                            rate = highRate;
                        }
                        double p;
                        p = rate / 12;
                        double capital = totalMoney / n;
                        for (int i = 1; i <= n; i++)
                        {

                            interest = totalMoney * p;
                            payMonth = capital + interest;
                            totalMoney -= capital;

                            Console.WriteLine("{0}		{1:0.00}			{2:0.00}		{3:0.00}	{4:0.00}", i, interest, capital, payMonth, totalMoney);
                        }
                    }
                    break;

            }
        }
        /// <summary>
        /// 计算还款状况
        /// </summary>
        /// <param name="n0">还款期数</param>
        /// <param name="dt">首次还款时间</param>
        void Repayment(int n0, DateTime dt)
        {
            balance = totalMoney;
            DateTime dt0 = dt;
            double rate0;
            double capital;
            double p;
            Console.WriteLine("还款时间		偿还利息		偿还本金		还款额		剩余本金");
            switch (choice)
            {
                case "1":
                    {
                        
                        RateChoose(dt0);
                        if (n0 <= 60)
                        {
                            rate0 = lowRate;
                        }
                        else
                        {
                            rate0 = highRate;
                        }
                        n = n0;
                        for (int i = 1; i <=n0; i++)
                        {
                            RateChoose(dt);
                            rate = (n0 <= 60 ? lowRate : highRate);
                            
                            if (dt.Year != dt0.Year && rate != rate0)//这里应该有问题？
                            {
                                double p0 = rate0 / 12;
                                double payMonth0= (p0 * totalMoney * Math.Pow((1 + p0), n)) / ((Math.Pow(1 + p0, n) - 1));
                                double interest0 = balance * p0;
                                double capital0 = payMonth0 - interest0;
                                
                                rate0 = rate;
                               
                                interest = balance * (rate0/12);
                                totalMoney = balance;
                                balance -= capital0;
                               
                                payMonth = capital0 + interest;
                                n =n0 - i+1;
                                Console.WriteLine("{0}	{1:0.00}			{2:0.00}			{3:0.00}		{4:0.00}", dt, interest, capital0, payMonth, balance);
                                dt = dt.AddMonths(1);
                                continue;
                            }


                           
                            p = rate0 / 12;
                            payMonth = (p * totalMoney * Math.Pow((1 + p), n)) / ((Math.Pow(1 + p, n) - 1));

                            interest = balance * p;
                             capital = payMonth - interest;
                            balance -= capital;
                            Console.WriteLine("{0}	{1:0.00}			{2:0.00}			{3:0.00}		{4:0.00}", dt, interest, capital, payMonth, balance);
                            dt = dt.AddMonths(1);

                        }

                    }
                    break;
                case "2":
                    {
                        RateChoose(dt0);
                        rate0 = (n0 <= 60 ? lowRate : highRate);
                        n = n0;
                        for (int i = 0; i < n0; i++)
                        {
                            RateChoose(dt);
                            rate = (n0 <= 60 ? lowRate : highRate);
                            if (dt.Year!=dt0.Year&&rate!=rate0)
                            {
                                rate0 = rate;
                            }
                            p = rate0 / 12;
                            capital = totalMoney / n0;
                            interest = balance * p;
                            payMonth = capital + interest;
                            balance -= capital;
                            Console.WriteLine("{0}	{1:0.00}			{2:0.00}			{3:0.00}		{4:0.00}", dt, interest, capital, payMonth, balance);
                            dt = dt.AddMonths(1);
                        }
                    }
                    break;
            }
        }
        /// <summary>
        ///实现提前还款功能
        /// </summary>
        /// <param name="n">还款总期数</param>
        /// <param name="dt1">首次还款时间</param>
        /// <param name="dt2">提前还款时间</param>
        void Prepayment(int n0,DateTime dt1,DateTime dt2,double money)
        {
            balance = totalMoney;
            DateTime dt0 = dt1;
            double rate0;
            double capital;
            double p;
            bool flag = false;
            Console.WriteLine("还款时间		偿还利息		偿还本金		还款额		剩余本金");
            switch (choice)
            {
                case "1":
                    {
                        RateChoose(dt0);
                        rate0 = (n0 <= 60 ? lowRate : highRate);
                        n = n0;
                        for(int i=1;i<=n0;i++)
                        {
                            RateChoose(dt1);
                            rate = (n0 <= 60 ? lowRate : highRate);
                           

                            if (dt1.Year != dt0.Year && rate != rate0)//这里应该有问题？
                            {
                                double p0 = rate0 / 12;
                                double payMonth0 = (p0 * totalMoney * Math.Pow((1 + p0), n)) / ((Math.Pow(1 + p0, n) - 1));
                                double interest0 = balance * p0;
                                double capital0 = payMonth0 - interest0;

                                rate0 = rate;

                                interest = balance * (rate0 / 12);
                                totalMoney = balance;
                                balance -= capital0;

                                payMonth = capital0 + interest;
                                n = n0 - i + 1;
                                Console.WriteLine("{0}	{1:0.00}			{2:0.00}			{3:0.00}		{4:0.00}", dt1, interest, capital0, payMonth, balance);
                                dt1 = dt1.AddMonths(1);
                                continue;
                            }



                            p = rate0 / 12;
                            if (dt2.Year == dt1.Year && dt2.Month == dt1.Month)
                            {
                                balance -= money;
                                totalMoney = balance;
                                switch (newChoice)
                                {
                                    case "1":
                                        {

                                            n = n0 - i + 1;
                                            flag = true;
                                        }
                                        break;
                                    case "2":
                                        {
                                            double temp = Math.Log((payMonth / (payMonth - totalMoney * p)), (1 + p));
                                            n= (int)Math.Ceiling(temp);
                                            n0 = n + i - 1;
                                        }
                                        break;
                                }

                            }
                            payMonth = (p * totalMoney * Math.Pow((1 + p), n)) / ((Math.Pow(1 + p, n) - 1));
                            

                            interest = balance * p;
                            capital = payMonth - interest;
                            balance -= capital;
                            if (flag)
                            {
                                payMonth += money;
                                capital += money;
                                flag = false;
                            }
                            Console.WriteLine("{0}	{1:0.00}			{2:0.00}			{3:0.00}		{4:0.00}", dt1, interest, capital, payMonth, balance);
                            dt1 = dt1.AddMonths(1);
                        }
                    }
                    break;
                case "2":
                    {

                    }
                    break;
            }
        }
        static void Main(string[] args)
        {

            {
                Program p = new Program();
                p.Paint();
                Console.WriteLine("请选择您的操作！1.房贷计算 2.月供速算 3.还款状况 4.提前还款");
                Console.WriteLine("请选择您的还款方式？1.等额本息 2.等额本金");
                choice = Console.ReadLine();
                Console.WriteLine("请输入你的贷款金额");
                totalMoney = Convert.ToDouble(Console.ReadLine());
                Console.WriteLine("请输入您贷款的期数");
                int number = Convert.ToInt32(Console.ReadLine());
                Console.WriteLine("请输入你的首次贷款时间");
                DateTime dT = Convert.ToDateTime(Console.ReadLine());
                Console.WriteLine("请输入你的提前还款时间");
                DateTime dTR = Convert.ToDateTime(Console.ReadLine());
                Console.WriteLine("请输入你的还款金额");
                double partMoney = Convert.ToDouble(Console.ReadLine());
                Console.WriteLine("请选择你要的后续操作！1.减少月供 2.缩短年限");
                 newChoice = Console.ReadLine();
                //Console.WriteLine("你输入的日期是{0}，短期利率是{1}，长期利率是{2}",dT,p.lowRate,p.highRate);
                //dT= dT.AddMonths(1);
                // Console.WriteLine(dT);
                // p.Repayment(number, dT);
                // p.Compute(number);
                // p.Payment(dTR);
                p.Prepayment(number, dT, dTR, partMoney);
                Console.ReadKey();
            }
        }
    }
}

    经过两三天的修改，代码进一步完善。但是鉴于自己水平有限，代码错误之处在所难免。不足之处，希望大家提出宝贵意见，使代码进一步完善。