using System.Xml;
            using System.Xml.XPath;

XPathNavigator nav;
            XPathDocument docNav;
            XPathNodeIterator NodeIter;
            String strExpression;

// Open the XML.
            docNav = new XPathDocument(@"c:\books.xml");

// Create a navigator to query with XPath.
            nav = docNav.CreateNavigator();

// Find the average cost of a book.
            // This expression uses standard XPath syntax.
            strExpression = "sum(/bookstore/book/price) div count(/bookstore/book/price)";

// Use the Evaluate method to return the evaluated expression.
            Console.WriteLine("The average cost of the books are {0}", nav.Evaluate(strExpression));

// Find the title of the books that are greater then $10.00.
            strExpression = "/bookstore/book/title[../price>10.00]";

// Select the node and place the results in an iterator.
            NodeIter = nav.Select(strExpression);

Console.WriteLine("List of expensive books:");
            //Iterate through the results showing the element value.
            while (NodeIter.MoveNext())
            {
            Console.WriteLine("Book Title:{0}", NodeIter.Current.Value);
            };

//Pause
            Console.ReadLine();