C# Merge Sort

mergesort.cs

using System;
using System.Collections;

namespace mergesort
{
	class MainClass
	{
		public static void Main(string[] args)
		{
			int count = Convert.ToInt32(Console.ReadLine());

			ArrayList toBeSortedA = new ArrayList();
			int[] toBeSortedB = new int[count];

			Random gen = new Random();

			Console.WriteLine("Unsorted");

			for (int i = 0; i < count; i++)
			{
				int rand = gen.Next(1, 200);

				toBeSortedA.Add(rand);

				toBeSortedB[i] = rand;

				Console.WriteLine(rand);

			}

			Console.WriteLine("");
			Console.WriteLine("");
			Console.WriteLine("Sorted:");



			MergeSorter ms = new MergeSorter();

			ms.MergeSort(toBeSortedB, 0, toBeSortedB.Length-1);

			foreach (int a in toBeSortedB)
			{
				Console.WriteLine(a);
			}
		}
	}

	class MergeSorter
	{
		public MergeSorter()
		{
		}

        
		public void MergeSort(int[] array, int left, int right)
		{
            //array -> to be sorted
            //left -> start point
            //right -> stop point
			if (left >= right) return;

			var mid = (left + right) / 2;
			MergeSort(array, left, mid);
			MergeSort(array, mid + 1, right);
			Merge(array, left, mid, right);
		}

		private void Merge(int[] array, int start, int mid, int end)
		{
			var temp = new int[end - start + 1];
			var leftIndex = start;
			var rightIndex = mid + 1;
			var arrayIndex = 0;

			while (leftIndex <= mid && rightIndex <= end)
			{
				if (array[leftIndex] <= array[rightIndex])
				{
					temp[arrayIndex] = array[leftIndex];
					leftIndex++;
				}
				else
				{
					temp[arrayIndex] = array[rightIndex];
					rightIndex++;
				}
				arrayIndex++;
			}

			while (leftIndex <= mid)
			{
				temp[arrayIndex] = array[leftIndex];
				leftIndex++;
				arrayIndex++;
			}

			while (rightIndex <= end)
			{
				temp[arrayIndex] = array[rightIndex];
				rightIndex++;
				arrayIndex++;
			}

			for (var i = 0; i < end - start + 1; i++)
			{
				array[start + i] = temp[i];
			}

		}

	}
}