Retrieve all documents from folders and sub-folders in a SharePoint document library using C#

I had some requirements from client, for fulfilling that I had to write a code for getting list of all documents from folders/sub-folders from a SharePoint library.

Below is the code which I used:



===========================MAIN METHOD================================

private void OCR_Document()
        {
            try
            {


                SPWebApplication webApp = SPWebApplication.Lookup(new Uri("webapplication URL"));
//iterates in each site and subsites
                foreach (SPSite site in webApp.Sites)
                {
                    foreach (SPWeb web in site.AllWebs)
                    {
     //iterates in each lists/libraries
                        foreach (SPList list in web.Lists)
                        {
      //selects only document libraries
                            if (Convert.ToString(list.BaseType) == "DocumentLibrary")
                            {        
       //check if document library contains folder
                                    if (list.Folders.Count > 0)
                                    {
                                                 
                                        SPQuery query = new SPQuery();
                                        query.Folder = list.RootFolder;
                                        
                                        SPListItemCollection itemCollection = web.Lists[list.RootFolder.ParentListId].GetItems(query);

                                        foreach (SPListItem subitem in itemCollection)
                                        {
          //iterate in each folder-subfolder, all folders will come into this loop
                                            
                                            if (subitem.ContentType.Name == "Folder")
                                            {
                                               iterateFolder(subitem.Folder);
                                            }
                                            else
                                            {
                                                //here you will get only files in subitem varialbe
            //write your code here for files
                                            }

                                        }
                                    }
                                    else
                                    {
                                        foreach (SPFile file in list.RootFolder.Files)
                                        {

                                            //here you will get only files
            //write your code here for files


                                        }

                                    }
                                
                            }
                        }
                    }
                }



            }
            catch
            {

                throw;
            }


        }

===========================ITERATE FOLDER METHOD====================

private void iterateFolder(SPFolder folder)
        {
            if (folder.SubFolders != null)
            {
   //check for subfolders
                foreach (SPFolder item in folder.SubFolders)
                {
                    //scroll through each subfolder and each child folder
                    iterateFolder(item.SubFolders.Folder);
                }
            }


            foreach (SPFile file in folder.Files)
            {
                
                 //here you will get only files
       //write your code here for files

            }


        }