/// <summary>
/// 检测一个C代码文件中的有效代码行数
/// </summary>
/// <param name="filename">文件名</param>
/// <returns>代码行数</returns>
public static int LinesOfCode(string filename)
{
 System.IO.StreamReader sr = System.IO.File.OpenText(filename);
 string s = sr.ReadToEnd();
 sr.Close();
 bool isLine = false;  //一行中拥有有效字符时为true，该行可记入代码行数
 bool isCommitLf = false; //注释/*...*/中出现至少一个折行时为true
 int lines = 0;    //代码行数统计
 for (int i = 0; i < s.Length; i++)
 {
  //无效字符
  if (s[i] == ' ' || s[i] == '\r' || s[i] == '\t')
  {
   continue;
  }
  //搜索到换行，若该行有有效字符
  if (s[i] == '\n')
  {
   if (isLine)
   {
    lines++;
    isLine = false;
   }
   continue;
  }
  //字符串，占多少行按多少行算
  if (s[i] == '\"')
  {
   while (true)
   {
    i++;
    //如果文件遍历完毕则强行中止
    if (i >= s.Length)
    {
     break;
    }
    //再次遇到字符'"'且前方没有或有偶数个'//'时，中止循环并退出
    if (s[i] == '\"')
    {
     int sign = 0, counter = 0;
     while (true)
     {
      sign++;
      if (i - sign < 0)
      {
       break;
      }
      else if (s[i - sign] == '\\')
      {
       counter++;
      }
      else
      {
       break;
      }
     }
     if (counter % 2 == 0)
     {
      break;
     }
    }
    //字符串中的换行，直接算作一行代码
    if (s[i] == '\n')
    {
     lines++;
     isLine = true;
    }
   }
   isLine = true;
   continue;
  }
  //遇到形如 /*...*/ 的注释
  if (s[i] == '/' && i < s.Length - 1)
  {
   if (s[i + 1] == '*')
   {
    i++;
    while (true)
    {
     i++;
     //如果文件遍历完毕则强行中止
     if (i >= s.Length)
     {
      break;
     }
     if (s[i] == '\n')
     {
      if (isCommitLf == false)
      {
       if (isLine == true)
       {
        lines++;
        isLine = false;
       }
       isCommitLf = true;
      }
     }
     if (s[i] == '*' && i < s.Length - 1)
     {
      if (s[i + 1] == '/')
      {
       i++;
       break;
      }
     }
    }
    isCommitLf = false;
    continue;
   }
  }
  //遇到形如 // 的注释
  if (s[i] == '/' && i < s.Length - 1 && s[i + 1] == '/')
  {
   if (isLine == true)
   {
    lines++;
    isLine = false;
   }
   while (true)
   {
    i++;
    if (i >= s.Length || s[i] == '\n')
    {
     break;
    }
   }
   continue;
  }
  //该行有了有效字符，算作一行
  isLine = true;
 }
 //最后一行可能没有字符'\n'结尾
 if (isLine)
 {
  lines++;
 }
 return lines;
}

/// <summary>
/// 检测一个文件夹中所有C代码的行数
/// </summary>
/// <param name="foldername">文件夹名称</param>
/// <returns>代码行数</returns>
public static int LinesOfFolder(string foldername)
{
 //行数统计
 int lines = 0;
 //文件夹信息
 System.IO.DirectoryInfo dif = new System.IO.DirectoryInfo(foldername);
 //遍历文件夹中的各子文件夹
 foreach (System.IO.DirectoryInfo di in dif.GetDirectories())
 {
  lines += LinesOfFolder(di.FullName);
 }
 //统计本文件夹中C语言文件代码
 foreach (System.IO.FileInfo f in dif.GetFiles())
 {
  if (f.Extension == ".cs" || f.Extension == ".cpp" ||
   f.Extension == ".c" || f.Extension == ".h")
  {
   lines += LinesOfCode(f.FullName);
  }
 }
 return lines;
}

static void Main(string[] args)
{
 Console.WriteLine("请输入要统计的文件或文件夹");
 Console.WriteLine("输入示例：checkfile:xxx / checkfolder:xxx");
 try
 {
  string order = Console.ReadLine();
  string[] temp = order.Split(':');
  if (temp.Length < 2)
  {
   Console.WriteLine("语法错误，程序结束");
  }
  switch (temp[0])
  {
   case "checkfile":
    {
     int count = LinesOfCode(order.Substring(10).Trim());
     Console.WriteLine("共有代码 " + count + " 行");
    } break;
   case "checkfolder":
    {
     int count = LinesOfFolder(order.Substring(12).Trim());
     Console.WriteLine("共有代码 " + count + " 行");
    } break;
   default: Console.WriteLine("未知命令"); break;
  }
 }
 catch (Exception ex)
 {
  Console.WriteLine(ex.Message);
 }
 Console.ReadLine();
}