//#define TEST

using System;
using System.Data;
using System.Drawing;
//using System.Windows.Forms; 
using System.IO;
using System.Collections.Specialized;
using System.Threading;
using System.Globalization;
using System.Runtime.InteropServices;


 
 class application
 {

   [STAThread]
   static void Main(string[] args)
   {
     byte[] buf4c = new byte[4]; 
     byte[] buf4n = new byte[4]; 
     int red = 0;
     int redn = 0;
     long pos = 0;
     int coin = 0;
     int number = 0;

     string me_ = "Main";
     using (FileStream rws = new FileStream
        ("data.bin", FileMode.Open))
     {   while ( ((red = rws.Read(buf4c, 0, 4)) ==4 ) && ((redn = rws.Read(buf4n, 0, 4)) ==4 ))   {
    //       if (BitConverter.IsLittleEndian)  {Array.Reverse(buf4c); Array.Reverse(buf4n); }
           coin   = BitConverter.ToInt32(buf4c, 0);
           number = BitConverter.ToInt32(buf4n, 0);
           pos    = rws.Position;
           Console.Error.WriteLine("next pair {0}:{1}/ {2}", coin, number, pos);
           rws.Seek (-4, SeekOrigin.Current);

           buf4n  =BitConverter.GetBytes(++number); 
           rws.Write(buf4n, 0, 4);
         }
         if (red !=0 || redn !=0){
            Console.Error.WriteLine("wrong length of file: {0}/{1}", red, redn);
         }
     } 

   }

}


//          gVars.log.wrLn("{0} is finished. rc: {1}; sid: {2}; newV/oldV/diff: {3}/{4}/{5} \n",
//                                            me_, rc, gVars.sid, newV, oldV, val);

     using (BinWriter w  = new BinWriter
        ("data.bin", FileMode.Open))
     {
       using ( BinReader r = new BinReader (w.BaseStream))
          {

      
       ....
          }

     }

  public unsafe virtual void Write(double value)
        {
            ulong TmpValue = *(ulong *)&value;
            _buffer[0] = (byte) TmpValue;
            _buffer[1] = (byte) (TmpValue >> 8);
            _buffer[2] = (byte) (TmpValue >> 16);
            _buffer[3] = (byte) (TmpValue >> 24);
            _buffer[4] = (byte) (TmpValue >> 32);
            _buffer[5] = (byte) (TmpValue >> 40);
            _buffer[6] = (byte) (TmpValue >> 48);
            _buffer[7] = (byte) (TmpValue >> 56);
            OutStream.Write(_buffer, 0, 8);
        }
 
        public virtual void Write(decimal value)
        {
            Decimal.GetBytes(value,_buffer);
            OutStream.Write(_buffer, 0, 16);
        }
    

     using (BinWriter w  = new BinWriter
        ("data.bin", FileMode.Open))
     {
       using ( BinReader r = new BinReader (w.BaseStream))
          {

      
       ....
          }

     }

     using (BinWriter w  = new BinWriter
         (File.Open("data.bin", FileMode.Open))  // <------------------
//        ("data.bin", FileMode.Open))
     {
       using ( BinReader r = new BinReader (w.BaseStream))
          {

      
       ....
          }

     }