How do you upload a file to a document library in SharePoint?

//fileUpload is ASP.Net FileUpload control.
        if (!string.IsNullOrEmpty(fileQuotation.FileName))
        {
            using (SPSite site = new SPSite(sitename))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    web.AllowUnsafeUpdates = true;
                    SPDocumentLibrary docLib
                        = web.Lists[documentLibraryName] as SPDocumentLibrary;

                    //Get file extension ( *.doc OR *.docx )
                    string fileExtension
                        = fileQuotation.FileName.Substring(fileQuotation.FileName.IndexOf("."));
                    byte[] fileBytes = fileQuotation.FileBytes;
                    string destUrl
                        = docLib.RootFolder.Url + "/" + "MyFileName" + fileExtension;
                    SPFile destFile = docLib.RootFolder.Files.Add(destUrl, fileBytes, true);
                    SPListItem item = destFile.Item;
                    item["Title"] = "Title";
                    item.Update();
                    destFile.Update();
                     
                   
                    web.AllowUnsafeUpdates = true;
                }
            }
        }