import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;

/**
 * @author: Andrea Michienzi
 */

public class EsercizioIO {
	
	public static void main(String[] args) throws IOException {
		
		String basedir="/path/to/dir/";
		File startDirectory=new File(basedir);
		if(!startDirectory.isDirectory()) {
			System.out.println("Initial file is not a directory!");
			return;
		}
		
		List<File> directories=new LinkedList<File>();
		directories.add(startDirectory);
		
		DataOutputStream d=new DataOutputStream(new BufferedOutputStream(new FileOutputStream(new File("directories"))));
		DataOutputStream f=new DataOutputStream(new BufferedOutputStream(new FileOutputStream(new File("files"))));
		
		while(directories.size()>0) {
			File[] filesInCurrentDirectory=directories.remove(0).listFiles();
			for(File ficd : filesInCurrentDirectory) {
				String towrite=ficd.getName().toString() + "\n";
				if(ficd.isDirectory()) {
					d.write(towrite.getBytes());
					directories.add(ficd);
				} else {
					f.write(towrite.getBytes());
				}
			}
		}
		
		
		d.flush();
		f.flush();
		d.close();
		f.close();
		
	}

}