class Strategy
    {
        public interface IStrategy
        {
            void Algorithm(string data);
        }

        public class ProcessingNumberSign : IStrategy
        {
            public void Algorithm(string data)
            {
                DoSomething(data);
            }

            private void DoSomething(string data)
            {
                throw new NotImplementedException();
            }
        }

        public class ProcessingAsterisk : IStrategy
        {
            public void Algorithm(string data)
            {

            }
        }

        class StreamProcesser
        {
            public void ProcessStream(Stream stream)
            {
                using (StreamReader sr = new StreamReader(stream))
                {
                    while (!sr.EndOfStream)
                    {
                        var symb = ReadSymbol(sr);
                        DoWork(sr, symb);
                    }
                }
            }

            private static string ReadSymbol(StreamReader sr)
            {
                var symb = sr.Read().ToString();
                return symb;
            }

            public static void DoWork(StreamReader sr, string op)
            {
                switch (op)
                {
                    case "#":
                        new ProcessingNumberSign().Algorithm(op);
                    break;
                    case "*":
                        StringBuilder dataStringBuilder = new StringBuilder();
                        int dataSum = 0;
                        while (!sr.EndOfStream)
                        {
                            var symb = ReadSymbol(sr);
                            if (symb == ";")
                                break;
                            dataStringBuilder.Append(symb);
                            dataSum += int.Parse(symb);
                        }

                        if (dataSum % 2 == 0)
                        {
                            new ProcessingAsterisk().Algorithm(dataStringBuilder.ToString());
                        }
                    break;
                }
            }
        }
    }