房貸計算器代碼

   本人嘗試著利用C#語言來寫一個房貸計算器控制台程式。由於剛開始學，錯誤與失誤之處會很多。希望大家多多批評指正，我會持續改進。謝謝大家。

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
{
//短期利率與長期利率
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);
//貸款金額
static double totalMoney, balance;

static string choice;
//期數
int n;
//月供
double payMonth;
double rate;
double interest;
/// <summary>
/// 用來構建歡迎界面
/// </summary>
void Paint()
{
Console.WriteLine("***************************");
Console.WriteLine("***************************");
Console.WriteLine("***************************");
Console.WriteLine("歡迎使用房貸計算器");
Console.WriteLine("***************************");
Console.WriteLine("***************************");
Console.WriteLine("***************************");

Console.WriteLine("請按任意鍵繼續");
Console.ReadKey();
Console.Clear();
}
/// <summary>
/// 按日期選擇利率
/// </summary>
/// <param name="dt">輸入的日期</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("你輸入的日期不在範圍內");
Console.ReadKey();
Environment.Exit(0);
}
}
/// <summary>
/// 計算月供
/// </summary>
void Payment(DateTime dt)
{
//設置緩衝區高度，即設置顯示的最大行數
Console.BufferHeight = 1000;
RateChoose(dt);
switch (choice)
{
case "1":
{
//等額本息，月供計算方法
for (n = 1; n <= 360; n++)
{

if (n <= 60)
{
rate = lowRate;
}
else
{
rate = highRate;
}
//計算月供
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}期按揭貸款的月供是{1:0.00}元，總利息是{2:0.00}元", n, payMonth, interest);

}
}
break;
case "2":
{
//等額本金，月供計算方法
for (n = 1; n <= 360; n++)
{
if (n <= 60)
{
rate = lowRate;
}
else
{
rate = highRate;
}
//計算月供
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}期按揭貸款的首月還款額是{1:0.00}元,總利息是{2:0.00}元", n, payMonth, interest);
}
}
break;
}
}

/// <summary>
/// 月貸計算方法
/// </summary>
/// <param name="n">還款期數</param>
void Compute(int n)
{
Console.WriteLine("期次\t\t償還利息\t\t償還本金\t\t還款額\t\t剩餘本金");
switch (choice)
{

case "1":
//等額本息法計算房貸
{
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}\t\t{1:0.00}\t\t{2:0.00}\t{3:0.00}\t{4:0.00}", i, interest, capital, payMonth, totalMoney);
}
}
break;
case "2":
//等額本金法計算房貸
{
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}\t\t{1:0.00}\t\t\t{2:0.00}\t\t{3:0.00}\t{4:0.00}", i, interest, capital, payMonth, totalMoney);
}
}
break;

}
}
/// <summary>
/// 計算還款狀況
/// </summary>
/// <param name="n0">還款期數</param>
/// <param name="dt">首次還款時間</param>
void Repayment(int n0, DateTime dt)
{
balance = totalMoney;
DateTime dt0 = dt;
Console.WriteLine("還款時間\t\t償還利息\t\t償還本金\t\t還款額\t\t剩餘本金");
switch (choice)
{
case "1":
{
double rate0;
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)//這裡應該有問題？
{
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}\t{1:0.00}\t\t\t{2:0.00}\t\t\t{3:0.00}\t\t{4:0.00}", dt, interest, capital0, payMonth, balance);
dt = dt.AddMonths(1);
continue;
}

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

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

}

}
break;
}
}
/// <summary>
///實現提前還款功能
/// </summary>
/// <param name="n">還款總期數</param>
/// <param name="dt1">首次還款時間</param>
/// <param name="dt2">提前還款時間</param>
void Prepayment(int n,DateTime dt1,DateTime dt2)
{

}
static void Main(string[] args)
{

{
Program p = new Program();
p.Paint();
Console.WriteLine("請選擇您的操作！1.房貸計算 2.月供速算 3.還款狀況 4.提前還款");
Console.WriteLine("請選擇您的還款方式？1.等額本息 2.等額本金");
choice = Console.ReadLine();
Console.WriteLine("請輸入你的貸款金額");
totalMoney = Convert.ToDouble(Console.ReadLine());
// Console.WriteLine("請輸入您貸款的期數");
// int number = Convert.ToInt32(Console.ReadLine());
// Console.WriteLine("請輸入你的首次貸款時間");
// DateTime dT = Convert.ToDateTime(Console.ReadLine());
Console.WriteLine("請輸入你的提前還款時間");
DateTime dTR = Convert.ToDateTime(Console.ReadLine());
//Console.WriteLine("請輸入你的還款金額");
//double partMoney = Convert.ToDouble(Console.ReadLine());
//Console.WriteLine("你輸入的日期是{0}，短期利率是{1}，長期利率是{2}",dT,p.lowRate,p.highRate);
//dT= dT.AddMonths(1);
// Console.WriteLine(dT);
//p.Repayment(number, dT);
// p.Compute(number);
p.Payment(dTR);
Console.ReadKey();
}
}
}
}