String Reversal This will print the string in reverse order.

        public string StringReversal(string stringToBeReversed)
        {
            string retStr = "";
            Stack chars = new Stack();
            foreach (char c in stringToBeReversed)
            {
                chars.Push(c);
            }
            while (chars.Count > 0)
            {
                Console.Write(chars.Pop());
            }
            Console.Read();
            
            return retStr = chars.ToString();
        }
  
    

Tokenizer This will print each word in phrase on separate line with punctuation removed using a Regular Expression.

         public List<string> tokenizer (String phrase) 
         {
            List<string> retList = new List<string>();
            phrase = Regex.Replace(phrase, @"[^\w\s]" , string.Empty);
            string[] tokens = phrase.Split(' ');
            foreach (string token in tokens)
            {
                retList.Add(token);
                Console.WriteLine(token);
            }
            Console.Read();
            Console.WriteLine(); // insert blank line
            
            return retList;
        }