/Hashtable Hashtable table = new Hashtable(); table.Add("userName", "sudheer"); table.Add("Password", "Reddy"); table.Add("Age", "32"); table.Add("Country", "India"); Console.ReadKey(); Console.WriteLine(table.Count); foreach (var key in table.Keys) Console.WriteLine(" " + key + ": " + table[key]); //Dictionary String[] names1 = new string[] { "sudheer", "kumar", "reddy", "chittireddy" }; String[] names2 = new string[] { "suresh", "kumar", "reddy", "chittiredd...