static void Main(string[] args)
{
Directory root = new Directory("My Directory");
File file1 = new File("File1");
File file2 = new File("File2");
File file3 = new File("File3");
Directory dir1 = new Directory("Dir1");
Directory dir2 = new Directory("Dir2");
Directory dir3 = new Directory("Dir3");
root.AddChild(file1);
root.AddChild(file2);
root.AddChild(dir1);
root.AddChild(dir2);
root.AddChild(dir3);
dir3.AddChild(file3);
PrintNodes(root);
Console.ReadKey();
}