using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.IO;

namespace ConsoleApplication1
{
    class Program
    {
        static IntPtr INVALID_HANDLE_VALUE = new IntPtr(-1);

        static uint FILE_ATTRIBUTE_DIRECTORY = 0x00000010;

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct WIN32_FIND_DATA
        {
            public uint dwFileAttributes;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftCreationTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastAccessTime;
            public System.Runtime.InteropServices.ComTypes.FILETIME ftLastWriteTime;
            public uint nFileSizeHigh;
            public uint nFileSizeLow;
            public uint dwReserved0;
            public uint dwReserved1;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string cFileName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
            public string cAlternateFileName;
        }

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr FindFirstFile(string lpFileName, out WIN32_FIND_DATA lpFindFileData);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATA lpFindFileData);

        [DllImport("kernel32.dll")]
        public static extern bool FindClose(IntPtr hFindFile);

        static void Main(string[] args)
        {
            foreach (var f in enumfiles("C:\\"))
            {
                Console.WriteLine(f.cFileName);
            }
        }

        static IEnumerable<WIN32_FIND_DATA> enumfiles(string dirname)
        {
            var stack = new Stack<string>();
            stack.Push(dirname);

            while (stack.Count > 0)
            {
                var present = stack.Pop();

                WIN32_FIND_DATA win32fd;
                IntPtr find = FindFirstFile(Path.Combine(present, "*"), out win32fd);
                if (find == INVALID_HANDLE_VALUE)
                {
                    continue;
                }

                do
                {
                    if ((win32fd.cFileName == ".") || (win32fd.cFileName == ".."))
                    {
                        continue;
                    }

                    win32fd.cFileName = Path.Combine(present, win32fd.cFileName);
                    if ((win32fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
                    {
                        yield return win32fd;
                    }
                    else
                    {
                        stack.Push(win32fd.cFileName);
                    }
                } while (FindNextFile(find, out win32fd));
                FindClose(find);
            }
        }
    }
}