XML C#

using System;
using System.Linq;
using System.Xml;
using System.Xml.Linq;
using System.Collections;
using System.Collections.Generic;
public class MainClass{
   public static void Main(){
            
      XmlWriterSettings settings = new XmlWriterSettings();
      settings.Indent = true;
      settings.IndentChars = ("    ");
      using (XmlWriter writer = XmlWriter.Create("books.xml", settings))
      {
          // Write XML data.
          writer.WriteStartElement("book");
          writer.WriteElementString("price", "19.95");
          writer.WriteEndElement();
          writer.Flush();
      }
   }
}