易百教程

using System;
using System.IO;

namespace FileIOApplication {

   class Program {

      static void Main(string[] args) {
         FileStream F = new FileStream("test.dat", FileMode.OpenOrCreate, 
            FileAccess.ReadWrite);

         for (int i = 1; i <= 20; i++) {
            F.WriteByte((byte)i);
         }

         F.Position = 0;
         for (int i = 0; i <= 20; i++) {
            Console.Write(F.ReadByte() + " ");
         }
         F.Close();
         Console.ReadKey();
      }
   }
}