I am using itextsharp for generating a pdf . the pdf that is generated is by default vertical. (a4 - vertical).?

using (FileStream fs = new FileStream(appRootDir + fileName, FileMode.Create, FileAccess.Write, FileShare.None))
               // Step 2: Creating iTextSharp.text.Document object


               using (Document doc = new Document(PageSize.A4))
               // Step 3: Creating iTextSharp.text.pdf.PdfWriter object
               // It helps to write the Document to the Specified FileStream

               using (PdfWriter writer = PdfWriter.GetInstance(doc, fs))
               {
                   doc.AddTitle("Example");
                   doc.AddSubject("This is an Example 4 of Chapter 1 of Book 'iText in Action'");
                   doc.AddKeywords("Metadata, iTextSharp 5.4.4, Chapter 1, Tutorial");
                   doc.AddCreator("iTextSharp 5.4.4");
                   doc.AddAuthor("RGU");
                   doc.AddHeader("Nothing", "No Header");


                   doc.Open();