using System;

using System.IO;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        foreach (var f in GetNewOrUpdatedFiles(".", "*.pdf", DateTime.Now))

        {

            Console.WriteLine(f);

        }       

    }

    public static List<string> GetNewOrUpdatedFiles(string path, string pattern, DateTime lastCheck)

    {

        DirectoryInfo dir = new DirectoryInfo(path);

        if (!dir.Exists)

            throw new DirectoryNotFoundException("The path does not exist.");

        FileSystemInfo[] nfos = dir.GetFileSystemInfos(pattern);

        return (from nfo in nfos

                where nfo.LastWriteTime > lastCheck

                select nfo.FullName).ToList();

    }

}