从M进制转换为N进制

    /// <summary>
    /// 从M进制转换为N进制
    /// </summary>
    internal class MBase2NBase
    {
        /// <summary>
        /// M进制值字符串
        /// </summary>
        private string MValue = "123";

        /// <summary>
        /// 除法商
        /// </summary>
        private string Quotient = null;

        /// <summary>
        /// M进制
        /// </summary>
        private int M = 10;

        /// <summary>
        /// N进制
        /// </summary>
        private int N = 8;

        /// <summary>
        /// .ctor
        /// </summary>
        public MBase2NBase()
        {
            
        }

        /// <summary>
        /// .ctor
        /// </summary>
        /// <param name="mValue">M进制值字符串</param>
        /// <param name="m">M进制(如10).参数值在2~36的范围内</param>
        /// <param name="n">N进制(如8),则意味着从10进制转换成8进制.参数值在2~36的范围内</param>
        public MBase2NBase(string mValue, int m, int n)
        {
            this.M = m;
            this.N = n;
            this.MValue = mValue;
        }

        /// <summary>
        /// 开始转换
        /// </summary>
        /// <param name="mValue">M进制值字符串</param>
        /// <param name="m">M进制(如10).参数值在2~36的范围内</param>
        /// <param name="n">N进制(如8),则意味着从10进制转换成8进制.参数值在2~36的范围内</param>
        /// <returns>N进制字符串</returns>
        public string Transform(string mValue, int m, int n)
        {
            this.M = m;
            this.N = n;
            this.MValue = mValue;
            return Transform();
        }

        /// <summary>
        /// M进制值字符串
        /// </summary>
        /// <returns>N进制字符串</returns>
        public string Transform()
        {
            if (M < 2 || M > 36)
            {
                throw new ArgumentOutOfRangeException("参数值不在2~36的范围内");
            }

            if (N < 2 || N > 36)
            {
                throw new ArgumentOutOfRangeException("参数值不在2~36的范围内");
            }

            if (M == N)
            {
                return MValue;
            }

            String nValue = "";
            Quotient = MValue;
            while (Quotient.Length > 0)
            {
                nValue = Remainder(Quotient) + nValue;
            }

            return nValue;
        }
        
        /// <summary>
        /// 对给定的M进制字符串对n求余
        /// </summary>
        /// <param name="mTempValue"></param>
        /// <returns></returns>
        private String Remainder(String mTempValue)
        {
            Quotient = "";
            int temp = 0;
            while (mTempValue.Length > 0)
            {
                int t = GetIntFromStringFirstChar(mTempValue.Substring(0, 1));
                mTempValue = mTempValue.Substring(1);
                temp = temp*M + t;
                Quotient += GetStrFromInt(temp / N);
                temp = temp%N;
            }
            while (Quotient.Length > 0 && Quotient[0] == '0')
            {
                Quotient = Quotient.Substring(1);
            }
            return GetStrFromInt(temp);
        }

        /// <summary>
        /// 字符串转换成Int
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        private int GetIntFromStringFirstChar(String str)
        {
            return str[0] <= '9' && str[0] >= '0' ? str[0] - '0' : str[0] - 'a' + 10;
        }

        /// <summary>
        /// Int转换为相应进制的字符
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        private String GetStrFromInt(int value)
        {
            String result = null;
            if (value >= 0 && value <= 9)
                result = ((char) ('0' + value)).ToString();
            else if (value > 9 && value < 36)
            {
                result = ((char) ('a' + value - 10)).ToString();
            }
            else
            {
                throw new Exception("未知错误");
            }

            return result;
        }
    }