Problem 5. Slicing File

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;

class Program
{
    static void Main()
    {
        string source = "../../SOLID - Logger.avi";
        string destination;
        int n = int.Parse(Console.ReadLine());

        List<string> collectedDestinations = new List<string>(n);

        for (int i = 0; i < n; i++)
        {
            destination = "Part-" + i + ".avi";
            collectedDestinations.Add(destination);
            Slice(source, destination, n);
        }


        string newSource = "../../assembled.avi";
        Assemble(collectedDestinations, newSource);
    }

    static void Slice(string sourceFile, string destinationDirectory, int parts)
    {
        using (var source = new FileStream(sourceFile, FileMode.Open))
        {
            using (var destination = new FileStream(destinationDirectory, FileMode.Create))
            {
                double fileLength = source.Length;
                byte[] buffer = new byte[4096];
                int sumOfReadBytes= 0;
                while (sumOfReadBytes< fileLength/ parts)
                {
                    int readBytes = source.Read(buffer, 0, buffer.Length);
                    sumOfReadBytes+= readBytes;
                    destination.Write(buffer, 0, readBytes);
                }
            }
        }
    }
    static void Assemble(List<string> files, string destinationDirectory)
    {
        var assembledFile = new FileStream(destinationDirectory, FileMode.Append);
        byte[] buffer = new byte[4096];

        using (assembledFile)
        {
            for (int i = 0; i < files.Count; i++)
            {
                var opener = new FileStream(files[i], FileMode.Open);
                using (opener)
                {
                    while (true)
                    {
                        int bytesRead = opener.Read(buffer, 0, buffer.Length);
                        if (bytesRead == 0)
                        {
                            break;
                        }
                        assembledFile.Write(buffer, 0, bytesRead);
                    }
                }
            }
        }
    }
}