Deflate algorithm is used to compress and uncompress files

        static void Main()
        {
            string path = @"D:\Practise\IO\Compress";
            string deCompressPath = @"D:\Practise\IO\DeCompress";
            DirectoryInfo dir = new DirectoryInfo(path);
            foreach (FileInfo fi in dir.GetFiles())
            {
                Compress(fi);
            }
            foreach (FileInfo fi in dir.GetFiles("*.cmp"))
            {
                DeCompress(fi, deCompressPath);
            }
        }
        public static void Compress(FileInfo fi)
        {
            using (FileStream fs = fi.OpenRead())
            {
                if (fi.Attributes != FileAttributes.Hidden & fi.Extension != ".cmp")
                {
                    using (FileStream compressfile = new FileStream(fi.FullName + ".cmp", FileMode.Create, FileAccess.ReadWrite))
                    {
                        using (DeflateStream ds = new DeflateStream(compressfile, CompressionMode.Compress))
                        {
                            fs.CopyTo(ds);
                            Console.WriteLine("This File {0} has been Compressed to {1}",fi.Name,compressfile.Name);
                        }
                    }
                }
            }
        }
        public static void DeCompress(FileInfo fi, string desination)
        {
            using (FileStream fs = fi.OpenRead())
            {
                string deCompressFile = fi.Name.Remove(fi.Name.Length - fi.Extension.Length);
                using (FileStream deCompressFS = new FileStream(Path.Combine(desination, deCompressFile), FileMode.Create, FileAccess.ReadWrite))
                {
                    using (DeflateStream ds = new DeflateStream(fs, CompressionMode.Decompress))
                    {
                        ds.CopyTo(deCompressFS);
                        Console.WriteLine("This file {0} has been Decompressd", fi.Name);
                    }
                }
            }
        }