C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;

public class Slide
{
    public string Text { get; init; }
    public Slide(string text)
    {
        Text = text;
    }
}
public class PdfDocument
{
    public void AddPage(string text)
    {
        Console.WriteLine("Adding a page to pdf");
    }
}
public class Movie
{
    public void AddFrame(string text, int duration)
    {
        Console.WriteLine("Adding a frame to movie");
    }
}
public enum PresentationFormat
{
    PDF,
    Movie
}

public interface IPresentationBuilder
{
    void AddSlide(Slide slide);
}
public class MovieBuilder : IPresentationBuilder
{
    Movie movie = new Movie();

    public void AddSlide(Slide slide)
    {
        movie.AddFrame(slide.Text, 10);
    }

    public Movie getMovie() { return movie; }
}
public class PdfDocumentBuilder : IPresentationBuilder
{
    PdfDocument pdfDocument = new PdfDocument();

    public void AddSlide(Slide slide)
    {
        pdfDocument.AddPage(slide.Text);
    }

    public PdfDocument GetPdfDocument() => pdfDocument;
}
public class Presentation
{
    List<Slide> slides = new List<Slide>();

    public void AddSlide(Slide slide)
    {
        slides.Add(slide);
    }

    public void Export(IPresentationBuilder builder)
    {
        foreach (var slide in slides)
        {
            builder.AddSlide(slide);
        }
    }
}
					
public class Program
{
	public static void Main()
	{
		var presentation = new Presentation();
		presentation.AddSlide(new Slide("Intro Page"));
		presentation.AddSlide(new Slide("Main Page"));
		presentation.AddSlide(new Slide("Summary Page"));

		var builder = new MovieBuilder();
		presentation.Export(builder);
		builder.getMovie();
		
		var builder2 = new PdfDocumentBuilder();
		presentation.Export(builder2);
		builder2.GetPdfDocument();
	}
}

    public PdfDocument GetPdfDocument() => pdfDocument;
 
using System;
using System.Collections.Generic;
​
public class Slide
{
    public string Text { get; init; }
    public Slide(string text)
    {
        Text = text;
    }
}
public class PdfDocument
{
    public void AddPage(string text)
    {
        Console.WriteLine("Adding a page to pdf");
    }
}
public class Movie
{
    public void AddFrame(string text, int duration)
    {
        Console.WriteLine("Adding a frame to movie");
    }

Cached Result

606.00
10,605.00
100,495.00