Detaillierte Einführung in den Fall der rekursiven Implementierung der chinesischen Funktion der digitalen Währungsumrechnung durch C# auf der Grundlage rein mathematischer Methoden

static void Main(string[] args)
{
Console.WriteLine("请输入金额");
string inputNum = Console.ReadLine();
while (inputNum != "exit")
{
//货币数字转化类
NumCast nc = new NumCast();
if (nc.IsValidated<string>(inputNum))
{
try
{
string chineseCharacter = nc.ConvertToChinese(inputNum);
Console.WriteLine(chineseCharacter);
}
catch (Exception er)
{
Console.WriteLine(er.Message);
}
}
else
{
Console.WriteLine("不合法的数字或格式");
}
Console.WriteLine("\n请输入金额");
inputNum = Console.ReadLine();
}
Console.ReadLine();
}

/// <summary>
/// 数位
/// </summary>
public enum NumLevel { Cent, Chiao, Yuan, Ten, Hundred, Thousand, TenThousand, hundredMillon, Trillion };
/// <summary>
/// 数位的指数
/// </summary>
private int[] NumLevelExponent = new int[] { -2, -1, 0, 1, 2, 3, 4, 8, 12 };
/// <summary>
/// 数位的中文字符
/// </summary>
private string[] NumLeverChineseSign = new string[] { "分", "角", "元", "拾", "佰", "仟", "万", "亿", "兆" };
/// <summary>
/// 大写字符
/// </summary>
private string[] NumChineseCharacter = new string[] {"零","壹","贰","叁","肆","伍","陆","柒","捌","玖"};
/// <summary>
/// 整(当没有 角分 时)
/// </summary>
private const string EndOfInt = "整";

/// <summary>
/// 正则表达验证数字是否合法
/// </summary>
/// <param name="Num"></param>
/// <returns></returns>
public bool IsValidated<T>(T Num)
{
Regex reg = new Regex(@"^(([0])|([1-9]\d{0,23}))(\.\d{1,2})?$");
if (reg.IsMatch(Num.ToString()))
{
return true;
}
return false;
}

/// <summary>
/// 获取数字的数位使用log
/// </summary>
/// <param name="Num"></param>
/// <returns></returns>
private NumLevel GetNumLevel(double Num)
{
double numLevelLength;
NumLevel NLvl = new NumLevel();
if (Num > 0)
{
numLevelLength = Math.Floor(Math.Log10(Num));
for (int i = NumLevelExponent.Length - 1; i >= 0; i--)
{
if (numLevelLength >= NumLevelExponent[i])
{
NLvl = (NumLevel)i;
break;
}
}
}
else
{
NLvl = NumLevel.Yuan;
}
return NLvl;
}

/// <summary>
/// 是否跳位
/// </summary>
/// <returns></returns>
private bool IsDumpLevel(double Num)
{
 if (Num > 0)
{
NumLevel? currentLevel = GetNumLevel(Num);
NumLevel? nextLevel = null;
int numExponent = this.NumLevelExponent[(int)currentLevel];
double postfixNun = Math.Round(Num % (Math.Pow(10, numExponent)),2);
if(postfixNun> 0)
nextLevel = GetNumLevel(postfixNun);
if (currentLevel != null && nextLevel != null)
{
if (currentLevel > nextLevel + 1)
{
return true;
}
}
}
return false;
}

/// <summary>
/// 是否大于兆，如果大于就把字符串分为两部分，
/// 一部分是兆以前的数字
/// 另一部分是兆以后的数字
/// </summary>
/// <param name="Num"></param>
/// <returns></returns>
private bool IsBigThanTillion(string Num)
{
bool isBig = false;
if (Num.IndexOf(&#39;.&#39;) != -1)
{
//如果大于兆
if (Num.IndexOf(&#39;.&#39;) > NumLevelExponent[(int)NumLevel.Trillion])
{
isBig = true;
}
}
else
{
//如果大于兆
if (Num.Length > NumLevelExponent[(int)NumLevel.Trillion])
{
isBig = true;
}
}
return isBig;
}
/// <summary>
/// 把数字字符串由‘兆&#39;分开两个
/// </summary>
/// <returns></returns>
private double[] SplitNum(string Num)
{
//兆的开始位
double[] TillionLevelNums = new double[2];
int trillionLevelLength;
if (Num.IndexOf(&#39;.&#39;) == -1)
trillionLevelLength = Num.Length - NumLevelExponent[(int)NumLevel.Trillion];
else
trillionLevelLength = Num.IndexOf(&#39;.&#39;) - NumLevelExponent[(int)NumLevel.Trillion];
//兆以上的数字
TillionLevelNums[0] = Convert.ToDouble(Num.Substring(0, trillionLevelLength));
//兆以下的数字
TillionLevelNums[1] = Convert.ToDouble(Num.Substring(trillionLevelLength ));
return TillionLevelNums;
}

bool isStartOfTen = false;
while (Num >=10)
{
if (Num == 10)
{
isStartOfTen = true;
break;
}
//Num的数位
NumLevel currentLevel = GetNumLevel(Num);
int numExponent = this.NumLevelExponent[(int)currentLevel];
Num = Convert.ToInt32(Math.Floor(Num / Math.Pow(10, numExponent)));
if (currentLevel == NumLevel.Ten && Num == 1)
{
isStartOfTen = true;
break;
}
}
return isStartOfTen;

/// <summary>
/// 合并分开的数组中文货币字符
/// </summary>
/// <param name="tillionNums"></param>
/// <returns></returns>
private string ContactNumChinese(double[] tillionNums)
{
string uptillionStr = CalculateChineseSign(tillionNums[0], NumLevel.Trillion, true, IsStartOfTen(tillionNums[0]));
string downtrillionStr = CalculateChineseSign(tillionNums[1], null, true,false);
string chineseCharactor = string.Empty;
//分开后的字符是否有跳位
if (GetNumLevel(tillionNums[1] * 10) == NumLevel.Trillion)
{
chineseCharactor = uptillionStr + NumLeverChineseSign[(int)NumLevel.Trillion] + downtrillionStr;
}
else
{
chineseCharactor = uptillionStr + NumLeverChineseSign[(int)NumLevel.Trillion];
if (downtrillionStr != "零元整")
{
chineseCharactor += NumChineseCharacter[0] + downtrillionStr;
}
else
{
chineseCharactor += "元整";
}
}
return chineseCharactor;
}

/// <summary>
/// 计算中文字符串
/// </summary>
/// <param name="Num">数字</param>
/// <param name="NL">数位级别 比如1000万的 数位级别为万</param>
/// <param name="IsExceptTen">是否以‘壹拾&#39;开头</param>
/// <returns>中文大写</returns>
public string CalculateChineseSign(double Num, NumLevel? NL ,bool IsDump,bool IsExceptTen)
{
Num = Math.Round(Num, 2);
bool isDump = false;
//Num的数位
NumLevel? currentLevel = GetNumLevel(Num);
int numExponent = this.NumLevelExponent[(int)currentLevel];
string Result = string.Empty;
//整除后的结果
int prefixNum;
//余数 当为小数的时候 分子分母各乘100
double postfixNun ;
if (Num >= 1)
{
prefixNum = Convert.ToInt32(Math.Floor(Num / Math.Pow(10, numExponent)));
postfixNun = Math.Round(Num % (Math.Pow(10, numExponent)), 2);
}
else
{
prefixNum = Convert.ToInt32(Math.Floor(Num*100 / Math.Pow(10, numExponent+2)));
postfixNun = Math.Round(Num * 100 % (Math.Pow(10, numExponent + 2)), 2);
postfixNun *= 0.01;
}
if (prefixNum < 10 )
{
//避免以‘壹拾&#39;开头
if (!(NumChineseCharacter[(int)prefixNum] == NumChineseCharacter[1]
&& currentLevel == NumLevel.Ten && IsExceptTen))
{
Result += NumChineseCharacter[(int)prefixNum];
}
else
{
IsExceptTen = false;
}
//加上单位
if (currentLevel == NumLevel.Yuan )
{
////当为 “元” 位不为零时 加“元”。
if (NL == null)
{
Result += NumLeverChineseSign[(int)currentLevel];
//当小数点后为零时 加 "整"
if (postfixNun == 0)
{
Result += EndOfInt;
}
}
}
else
{
Result += NumLeverChineseSign[(int)currentLevel];
}
 //当真正的个位为零时加上“元”
if (NL == null && postfixNun < 1 && currentLevel > NumLevel.Yuan && postfixNun > 0)
{
Result += NumLeverChineseSign[(int)NumLevel.Yuan];
}
}
else
{
//当 前缀数字未被除尽时， 递归下去
NumLevel? NextNL = null;
if ((int)currentLevel >= (int)(NumLevel.TenThousand))
NextNL = currentLevel;
Result += CalculateChineseSign((double)prefixNum, NextNL, isDump, IsExceptTen);
if ((int)currentLevel >= (int)(NumLevel.TenThousand))
{
Result += NumLeverChineseSign[(int)currentLevel];
}
}
//是否跳位
// 判断是否加零， 比如302 就要给三百 后面加零，变为 三百零二。
if (IsDumpLevel(Num))
{
Result += NumChineseCharacter[0];
isDump = true;
}
//余数是否需要递归
if (postfixNun > 0)
{
Result += CalculateChineseSign(postfixNun, NL, isDump, false);
}
else if (postfixNun == 0 && currentLevel > NumLevel.Yuan )
{
//当数字是以零元结尾的加上 元整 比如1000000一百万元整
if (NL == null)
{
Result += NumLeverChineseSign[(int)NumLevel.Yuan];
Result += EndOfInt;
}
}
return Result;
}

/// <summary>
/// 外部调用的转换方法
/// </summary>
/// <param name="Num"></param>
/// <returns></returns>
public string ConvertToChinese(string Num)
{
if (!IsValidated<string>(Num))
{
throw new OverflowException("数值格式不正确，请输入小于9999亿兆的数字且最多精确的分的金额！");
}
string chineseCharactor = string.Empty;
if (IsBigThanTillion(Num))
{
double[] tillionNums = SplitNum(Num);
chineseCharactor = ContactNumChinese(tillionNums);
}
else
{
double dNum = Convert.ToDouble(Num);
chineseCharactor = CalculateChineseSign(dNum, null, true, IsStartOfTen(dNum));
}
return chineseCharactor;
}