C#字符串自增自减算法详解

/// <summary> /// 字符串运算 /// </summary> public class StringOperation {  /// <summary>  /// 通过ASCII码值，对字符串自增1  /// </summary>  /// <param name="pStr">输入字符串</param>  /// <returns></returns>  public static string StringIncreaseOne(string pStr)  {   var vRetStr = pStr;   if (0 == pStr.Length)   {    vRetStr = "1";   }   else   {    // 将最后一个字符与之前的字符串分开    string vOtherStr = pStr.Substring(0, pStr.Length - 1);    int vIntChar = (int)pStr[pStr.Length - 1]; //转ASCII码值    if (48 <= vIntChar && vIntChar <= 57) //是数字（0 - 9）    {     vIntChar++; //自增1     if (vIntChar == 58) // 进一位     {      vIntChar = 48;      vOtherStr = StringIncreaseOne(vOtherStr);     }    }    else if (65 <= vIntChar && vIntChar <= 90) //是字母（A - Z）    {     vIntChar++; //自增1     if (vIntChar == 91)      {      vIntChar = 65;      vOtherStr = StringIncreaseOne(vOtherStr);     }    }    else if (97 <= vIntChar && vIntChar <= 122) //是字母（a - z）    {     vIntChar++; //自增1     if (vIntChar == 123)     {      vIntChar = 97;      vOtherStr = StringIncreaseOne(vOtherStr);      }    }    else // 其它字符 -> 跳过    {     vOtherStr = StringIncreaseOne(vOtherStr);    }    vRetStr = vOtherStr + (char)vIntChar;   }   return vRetStr;  }  /// <summary>  /// 通过ASCII码值，对字符串自减1  /// </summary>  /// <param name="pStr">输入字符串</param>  /// <returns></returns>  public static string StringReducingOne(string pStr)  {   var vRetStr = pStr;   if (0 == pStr.Length)   {    vRetStr = "9";   }   else   {    string vOtherStr = pStr.Substring(0, pStr.Length - 1);    int vIntChar = (int)pStr[pStr.Length - 1]; //转ASCII码值    if (48 <= vIntChar && vIntChar <= 57) //是数字（0 - 9）    {     vIntChar--;     if (vIntChar == 47)     {      vIntChar = 57;      vOtherStr = StringReducingOne(vOtherStr);     }    }    else if (65 <= vIntChar && vIntChar <= 90) //是数字（A - Z）    {     vIntChar--;      if (vIntChar == 64)     {      vIntChar = 90;      vOtherStr = StringReducingOne(vOtherStr);     }    }    else if (97 <= vIntChar && vIntChar <= 122) //是数字（a - z）    {     vIntChar--;     if (vIntChar == 96)     {      vIntChar = 122;      vOtherStr = StringReducingOne(vOtherStr);     }    }    else // 其它字符 -> 跳过    {     vOtherStr = StringReducingOne(vOtherStr);    }    vRetStr = vOtherStr + (char)vIntChar;   }   return vRetStr;  }  /// <summary>  /// 通过ASCII码值，对字符串自增  /// </summary>  /// <param name="pStr">输入字符串</param>  /// <param name="pCount">自增个数</param>  /// <returns></returns>  public static string StringIncrease(string pStr, int pCount)  {   string vRetStr = pStr;   for (int i = 0; i < pCount; i++)   {    vRetStr = StringIncreaseOne(vRetStr);   }   return vRetStr;  }  /// <summary>  /// 通过ASCII码值，对字符串自减  /// </summary>  /// <param name="pStr">输入字符串</param>  /// <param name="pCount">自减个数</param>  /// <returns></returns>  public static string StringReducing(string pStr, int pCount)  {   string vRetStr = pStr;   for (int i = 0; i < pCount; i++)   {    vRetStr = StringReducingOne(vRetStr);   }      return vRetStr;  }   }