Array.BinarySearch

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ArrayBinSearch
{
    class Program
    {
        static void Main(string[] args)
        {
            //Task 4: Write a program, that reads from the console an array of N integers and an integer K,
            //sorts the array and using the method Array.BinSearch() finds the largest number in the array which is ≤ K.

            Console.WriteLine("Please enter 'N' number: ");
            int N = int.Parse(Console.ReadLine());
            Console.WriteLine("Please enter 'K' number: ");
            int K = int.Parse(Console.ReadLine());
            List<int> array = new List<int>();

            for (int i = 0; i < N; i++)
            {
                Console.WriteLine("Please enter {0} number of the array: ", i + 1);
                array.Add(int.Parse(Console.ReadLine()));
            }

            array.Sort();

            int index = array.BinarySearch(K);

            if (index > 0) //The 'K' is found in the array;
            {
                Console.WriteLine("The element {0} to search for is at index {1}.", K, index);
                return;
            }
            else
            {
                array.Add(K); //Insert the 'K' in array;
                array.Sort();
            }

            int indexK = array.IndexOf(K); //Find the index of 'K' in the array;

            if ((K <= array[N]) && (K > array[0])) //The 'K' is not found in the array, but I put it in array, sort array again and print the number before 'K'.
            {

                Console.WriteLine("The element {0} to search for is not found. The next larger element is {1}.", K, array[indexK - 1]);
            }

            if (K == array[0]) //Print the index of number after 'K' if it is small of anyone else. If the 'K' exist it place will be before all numbers.
            {
                Console.WriteLine("No such number found.");
            }
        }
    }
}