using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XElement firstParticipant;
        XDocument xDocument  = new XDocument(
         new XDeclaration("1.0", "UTF-8", "yes"),
         new XDocumentType("Books", null, "Books.dtd", null),
         new XProcessingInstruction("Book", "out-of-print"),
         new XElement("Books", firstParticipant =
         new XElement("Book",
         new XComment("This is a new author."),
         new XProcessingInstruction("AuthorHandler", "new"),
         new XAttribute("type", "Author"),
         new XElement("FirstName", "J"),
         new XElement("LastName", "R")),
         new XElement("Book",
         new XAttribute("type", "Author"),
         new XElement("FirstName", "E"),
         new XElement("LastName", "B"))));

        foreach (XNode node in firstParticipant.Elements()) {
            Console.WriteLine(node);
        }
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XDocument xDocument = new XDocument(
         new XElement("Books",
           new XElement("Book",
            new XAttribute("type", "Author"),
            new XElement("FirstName", "A"),
           new XElement("LastName", "B")),
           new XElement("Book",
            new XAttribute("type", "Author"),
           new XElement("FirstName", "C"),
           new XElement("LastName", "D"))));

        IEnumerable<XElement> elements = xDocument.Element("Books").Elements("Book");
        foreach (XElement element in elements) {
            Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value);
        }
        foreach (XAttribute attribute in elements.Attributes("type")) {
            Console.WriteLine("Attribute: {0} : value = {1}",
             attribute.Name, attribute.Value);
        }
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XDocument xDocument = new XDocument(
         new XElement("Books",
           new XElement("Book",
            new XAttribute("type", "Author"),
            new XElement("FirstName", "A"),
           new XElement("LastName", "B")),
           new XElement("Book",
            new XAttribute("type", "Author"),
           new XElement("FirstName", "C"),
           new XElement("LastName", "D"))));

        IEnumerable<XElement> elements = xDocument.Element("Books").Elements("Book");
        foreach (XElement element in elements) {
            Console.WriteLine("Source element: {0} : value = {1}", element.Name, element.Value);
        }
        foreach (XAttribute attribute in elements.Attributes()) {
            Console.WriteLine("Attribute: {0} : value = {1}",
             attribute.Name, attribute.Value);
        }

    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XElement firstParticipant;
        XDocument xDocument  = new XDocument(
          new XElement("Books", firstParticipant =
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XAttribute("experience", "first-time"),
              new XElement("FirstName", "J"),
              new XElement("LastName", "R"))));

        Console.WriteLine(xDocument);
        firstParticipant.Attribute("experience").Value = "beginner";
        Console.WriteLine(xDocument);
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XElement firstParticipant;
        XDocument xDocument = new XDocument(
          new XElement("Books", firstParticipant =
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XAttribute("experience", "first-time"),
              new XElement("FirstName", "J"),
              new XElement("LastName", "R"))));

        Console.WriteLine(xDocument);
        firstParticipant.SetAttributeValue("type", "beginner");
        firstParticipant.SetAttributeValue("language", "English");
        firstParticipant.SetAttributeValue("experience", null);
        Console.WriteLine(xDocument);
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XElement firstParticipant;
        XDocument xDocument = new XDocument(
          new XElement("Books", firstParticipant =
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XAttribute("experience", "first-time"),
              new XElement("FirstName", "A"),
              new XElement("LastName", "B"))));

        Console.WriteLine(xDocument);
        firstParticipant.Attributes().Remove();
        Console.WriteLine(xDocument);
    }
}

    

   
 

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
    public static void Main() {
        XElement firstParticipant;
        XDocument xDocument = new XDocument(
          new XElement("Books", firstParticipant =
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XElement("FirstName", "J"),
              new XElement("LastName", "R"))));
        Console.WriteLine(xDocument);
        firstParticipant.Attribute("type").Remove();
        Console.WriteLine(xDocument);
    }
}