C#基于纯数学方法递归实现货币数字转换中文功能详解

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('.') != -1){//如果大于兆if (Num.IndexOf('.') > 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'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('.') == -1)trillionLevelLength = Num.Length - NumLevelExponent[(int)NumLevel.Trillion];elsetrillionLevelLength = Num.IndexOf('.') - 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'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100double 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'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;}