using System;
using System.IO;
using System.Xml;
public class Sample {
public static void Main() {
XmlDocument doc = new XmlDocument();
doc.Load("booksort.xml");
XmlNode book;
XmlNode root = doc.DocumentElement;
book=root.SelectSingleNode("descendant::book[author/last-name='A']");
book.LastChild.InnerText="15.95";
doc.Save(Console.Out);
}
}