本文實例講述了C#基于純數學方法遞歸實現貨幣數字轉換中文功能。分享給大家供大家參考，具體如下：
最近由于項目的原因，需要寫一個貨幣數字轉換中文的算法，先在網了找了一下，結果發現無一列外都是用(Replace)替換的方式來實現的，所以想寫個另外的算法；因為本人是學數學出身的，所以用純數學的方法實現。
注意：本文中的算法支持小于1023 (也就是9999億兆)貨幣數字轉化。
貨幣中文說明： 在說明代碼之前，首先讓我們回顧一下貨幣的讀法。
10020002.23 讀為 壹仟零貳萬零貳元貳角叁分
1020 讀為 壹仟零貳拾元整。
100000 讀為 拾萬元整
0.13 讀為 壹角叁分
代碼：
測試工程
static void Main(string[] args){Console.WriteLine("請輸入金額");string inputNum = Console.ReadLine();while (inputNum != "exit"){//貨幣數字轉化類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("不合法的數字或格式");}Console.WriteLine("/n請輸入金額");inputNum = Console.ReadLine();}Console.ReadLine();}貨幣轉化類（NumCast類）功能介紹
1. 常量的規定
/// <summary>/// 數位/// </summary>public enum NumLevel { Cent, Chiao, Yuan, Ten, Hundred, Thousand, TenThousand, hundredMillon, Trillion };/// <summary>/// 數位的指數/// </summary>private int[] NumLevelExponent = new int[] { -2, -1, 0, 1, 2, 3, 4, 8, 12 };/// <summary>/// 數位的中文字符/// </summary>private string[] NumLeverChineseSign = new string[] { "分", "角", "元", "拾", "佰", "仟", "萬", "億", "兆" };/// <summary>/// 大寫字符/// </summary>private string[] NumChineseCharacter = new string[] {"零","壹","貳","叁","肆","伍","陸","柒","捌","玖"};/// <summary>/// 整(當沒有 角分 時)/// </summary>private const string EndOfInt = "整";2. 數字合法性驗證，采用正則表達式驗證
/// <summary>/// 正則表達驗證數字是否合法/// </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;}3. 獲取數位 例如 1000的數位為 NumLevel.Thousand
/// <summary>/// 獲取數字的數位使用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;}4. 判斷數字之間是否有跳位，也就是中文中間是否要加零，例如1020 就應該加零。
/// <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;}5. 把長數字分割為兩個較小的數字數組，例如把9999億兆，分割為9999億和0兆，因為計算機不支持過長的數字。
/// <summary>/// 是否大于兆，如果大于就把字符串分為兩部分，/// 一部分是兆以前的數字/// 另一部分是兆以后的數字/// </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>/// 把數字字符串由‘兆'分開兩個/// </summary>/// <returns></returns>private double[] SplitNum(string Num){//兆的開始位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];//兆以上的數字TillionLevelNums[0] = Convert.ToDouble(Num.Substring(0, trillionLevelLength));//兆以下的數字TillionLevelNums[1] = Convert.ToDouble(Num.Substring(trillionLevelLength ));return TillionLevelNums;}6. 是否以“壹拾”開頭，如果是就可以把它變為“拾”
bool isStartOfTen = false;while (Num >=10){if (Num == 10){isStartOfTen = true;break;}//Num的數位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;7. 合并大于兆連個數組轉化成的貨幣字符串
/// <summary>/// 合并分開的數組中文貨幣字符/// </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;//分開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;}8. 遞歸計算貨幣數字的中文
/// <summary>/// 計算中文字符串/// </summary>/// <param name="Num">數字</param>/// <param name="NL">數位級別 比如1000萬的 數位級別為萬</param>/// <param name="IsExceptTen">是否以‘壹拾'開頭</param>/// <returns>中文大寫</returns>public string CalculateChineseSign(double Num, NumLevel? NL ,bool IsDump,bool IsExceptTen){Num = Math.Round(Num, 2);bool isDump = false;//Num的數位NumLevel? currentLevel = GetNumLevel(Num);int numExponent = this.NumLevelExponent[(int)currentLevel];string Result = string.Empty;//整除后的結果int prefixNum;//余數 當為小數的時候 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'開頭if (!(NumChineseCharacter[(int)prefixNum] == NumChineseCharacter[1]&& currentLevel == NumLevel.Ten && IsExceptTen)){Result += NumChineseCharacter[(int)prefixNum];}else{IsExceptTen = false;}//加上單位if (currentLevel == NumLevel.Yuan ){////當為 “元” 位不為零時 加“元”。if (NL == null){Result += NumLeverChineseSign[(int)currentLevel];//當小數點后為零時 加 "整"if (postfixNun == 0){Result += EndOfInt;}}}else{Result += NumLeverChineseSign[(int)currentLevel];} //當真正的個位為零時加上“元”if (NL == null && postfixNun < 1 && currentLevel > NumLevel.Yuan && postfixNun > 0){Result += NumLeverChineseSign[(int)NumLevel.Yuan];}}else{//當 前綴數字未被除盡時， 遞歸下去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// 判斷是否加零， 比如302 就要給三百 后面加零，變為 三百零二。if (IsDumpLevel(Num)){Result += NumChineseCharacter[0];isDump = true;}//余數是否需要遞歸if (postfixNun > 0){Result += CalculateChineseSign(postfixNun, NL, isDump, false);}else if (postfixNun == 0 && currentLevel > NumLevel.Yuan ){//當數字是以零元結尾的加上 元整 比如1000000一百萬元整if (NL == null){Result += NumLeverChineseSign[(int)NumLevel.Yuan];Result += EndOfInt;}}return Result;}9. 外部調用的轉換方法。
/// <summary>/// 外部調用的轉換方法/// </summary>/// <param name="Num"></param>/// <returns></returns>public string ConvertToChinese(string Num){if (!IsValidated<string>(Num)){throw new OverflowException("數值格式不正確，請輸入小于9999億兆的數字且最多精確的分的金額！");}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;}小結：
個人認為程序的靈魂是算法，大到一個系統中的業務邏輯，小到一個貨幣數字轉中文的算法，處處都體現一種邏輯思想。
是否能把需求抽象成一個好的數學模型，直接關系到程序的實現的復雜度和穩定性。在一些常用功能中想些不一樣的算法，對我們開拓思路很有幫助。
希望本文所述對大家C#程序設計有所幫助。
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