C# Part II Arrays Exercise 6 with Array.Sort

using System;

class MaxSum
{
    static void Main()
    {
        uint arrayLength = 0;

        Console.Write("Enter the arrays's length: ");

        while (!uint.TryParse(Console.ReadLine(), out arrayLength))
        {
            Console.Write("Invalid input. Enter a positive integer number: ");
        }

        int elementsCount = 0;

        Console.Write("Enter the count of the elements to be summed: ");

        while (!int.TryParse(Console.ReadLine(), out elementsCount) || elementsCount > arrayLength)
        {
            Console.Write("Invalid input. Enter a positive integer number: ");
        }

        int[] array = new int[arrayLength];

        for (int i = 0; i < arrayLength; i++)
        {
            Console.Write("Enter the {0} element of the array: ", i);

            while (!int.TryParse(Console.ReadLine(), out array[i]))
            {
                Console.Write("Invalid input. Enter an integer number: ");
            }
        }

        Array.Sort(array);

        int[] maxElements = new int[elementsCount];
        int maxSum = 0;

        for (int i = elementsCount - 1, len = array.Length - 1; i >= 0; i--, len--)
        {
            maxElements[i] = array[len];
            maxSum += maxElements[i];
        }

        Console.WriteLine("The maximal sum of {0} elements is the sum of the elements {1}, which is {2}.", elementsCount, string.Join(", ", maxElements), maxSum);

    }
}