数字转英文货币

using System;

namespace ConsoleApplication1 {
    internal class Program {
        private static void Main(string[] args) {
            Console.WriteLine(new Number2English().NumberToString(297561.74));
            Console.ReadLine();
        }
    }

    public class Number2English {
        private readonly string[] StrNO = new string[19];
        private readonly string[] StrTens = new string[9];
        private readonly string[] Unit = new string[8];

        public string NumberToString(double Number) {
            string Str;
            string BeforePoint;
            string AfterPoint;
            string tmpStr;
            int nBit;
            string CurString;
            int nNumLen;
            Init();
            Str = Convert.ToString(Math.Round(Number, 2));
            if (Str.IndexOf(".") == -1) {
                BeforePoint = Str;
                AfterPoint = "";
            } else {
                BeforePoint = Str.Substring(0, Str.IndexOf("."));
                AfterPoint = Str.Substring(Str.IndexOf(".") + 1, Str.Length - Str.IndexOf(".") - 1);
            }
            if (BeforePoint.Length > 12) {
                return null;
            }
            Str = "";
            while (BeforePoint.Length > 0) {
                nNumLen = Len(BeforePoint);
                if (nNumLen % 3 == 0) {
                    CurString = Left(BeforePoint, 3);
                    BeforePoint = Right(BeforePoint, nNumLen - 3);
                } else {
                    CurString = Left(BeforePoint, (nNumLen % 3));
                    BeforePoint = Right(BeforePoint, nNumLen - (nNumLen % 3));
                }
                nBit = Len(BeforePoint) / 3;
                tmpStr = DecodeHundred(CurString);
                if ((BeforePoint == Len(BeforePoint).ToString() || nBit == 0) && Len(CurString) == 3) {
                    if (Convert.ToInt32(Left(CurString, 1)) != 0 & Convert.ToInt32(Right(CurString, 2)) != 0) {
                        tmpStr = Left(tmpStr, tmpStr.IndexOf(Unit[3]) + Len(Unit[3])) + Unit[7] + " " +
                                 Right(tmpStr, Len(tmpStr) - (tmpStr.IndexOf(Unit[3]) + Len(Unit[3])));
                    } else {
                        tmpStr = Unit[7] + " " + tmpStr;
                    }
                }
                if (nBit == 0) {
                    Str = Convert.ToString(Str + " " + tmpStr).Trim();
                } else {
                    Str = Convert.ToString(Str + " " + tmpStr + " " + Unit[nBit - 1]).Trim();
                }
                if (Left(Str, 3) == Unit[7]) {
                    Str = Convert.ToString(Right(Str, Len(Str) - 3)).Trim();
                }
                if (BeforePoint == Len(BeforePoint).ToString()) {
                    return "";
                }
            }
            BeforePoint = Str;
            if (Len(AfterPoint) > 0) {
                AfterPoint = Unit[5] + " " + DecodeHundred(AfterPoint) + " " + Unit[6];
            } else {
                AfterPoint = Unit[4];
            }
            return (BeforePoint + " " + AfterPoint).ToUpper();
        }

        private void Init() {
            if (StrNO[0] != "One") {
                StrNO[0] = "One";
                StrNO[1] = "Two";
                StrNO[2] = "Three";
                StrNO[3] = "Four";
                StrNO[4] = "Five";
                StrNO[5] = "Six";
                StrNO[6] = "Seven";
                StrNO[7] = "Eight";
                StrNO[8] = "Nine";
                StrNO[9] = "Ten";
                StrNO[10] = "Eleven";
                StrNO[11] = "Twelve";
                StrNO[12] = "Thirteen";
                StrNO[13] = "Fourteen";
                StrNO[14] = "Fifteen";
                StrNO[15] = "Sixteen";
                StrNO[16] = "Seventeen";
                StrNO[17] = "Eighteen";
                StrNO[18] = "Nineteen";
                StrTens[0] = "Ten";
                StrTens[1] = "Twenty";
                StrTens[2] = "Thirty";
                StrTens[3] = "Forty";
                StrTens[4] = "Fifty";
                StrTens[5] = "Sixty";
                StrTens[6] = "Seventy";
                StrTens[7] = "Eighty";
                StrTens[8] = "Ninety";
                Unit[0] = "Thousand";
                Unit[1] = "Million";
                Unit[2] = "Billion";
                Unit[3] = "Hundred";
                Unit[4] = "Only";
                Unit[5] = "Dollars and";
                Unit[6] = "Cent";
                Unit[7] = "";
            }
        }

        private string DecodeHundred(string HundredString) {
            int tmp;
            string rtn = "";
            if (Len(HundredString) > 0 && Len(HundredString) <= 3) {
                switch (Len(HundredString)) {
                case 1:
                    tmp = Convert.ToInt32(HundredString);
                    if (tmp != 0) {
                        rtn = StrNO[tmp - 1];
                    }
                    break;
                case 2:
                    tmp = Convert.ToInt32(HundredString);
                    if (tmp != 0) {
                        if ((tmp < 20)) {
                            rtn = StrNO[tmp - 1];
                        } else {
                            if (Convert.ToInt32(Right(HundredString, 1)) == 0) {
                                rtn = StrTens[Convert.ToInt32(tmp / 10) - 1];
                            } else {
                                rtn =
                                        Convert.ToString(StrTens[Convert.ToInt32(tmp / 10) - 1] + " " +
                                                         StrNO[Convert.ToInt32(Right(HundredString, 1)) - 1]);
                            }
                        }
                    }
                    break;
                case 3:
                    if (Convert.ToInt32(Left(HundredString, 1)) != 0) {
                        rtn =
                                Convert.ToString(StrNO[Convert.ToInt32(Left(HundredString, 1)) - 1] + " " + Unit[3] +
                                                 "AND " +
                                                 DecodeHundred(Right(HundredString, 2)));
                    } else {
                        rtn = DecodeHundred(Right(HundredString, 2));
                    }
                    break;
                default:
                    break;
                }
            }
            return rtn;
        }

        private string Left(string str, int n) {
            return str.Substring(0, n);
        }

        private string Right(string str, int n) {
            return str.Substring(str.Length - n, n);
        }

        private int Len(string str) {
            return str.Length;
        }
    }
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/cppfaq/archive/2009/03/27/4030641.aspx