C#-Code

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

namespace haeufigstesElementInArray102
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] blub = new int[100];
            Dictionary<int, int> mostCommonElements = new Dictionary<int, int>();

            fillArray(ref blub, blub.Length);
            getMostCommonElements(ref mostCommonElements, ref blub);

            Console.BackgroundColor = ConsoleColor.White;
            Console.ForegroundColor = ConsoleColor.Black;
            Console.WriteLine("Zahl\t\tAnzahl");
            Console.ResetColor();
            foreach (var element in mostCommonElements.OrderByDescending(key => key.Value))
            {
                Console.WriteLine("{0}\t=>\t{1}", element.Key, element.Value);
            }

            Console.WriteLine("-------------------------------------");
            Console.WriteLine("Einzigartige Zahlen\t=>\t{0}", mostCommonElements.Count);
            Console.ReadKey();
        }

        private static void getMostCommonElements(ref Dictionary<int, int> mostCommonElements, ref int[] blub)
        {
            int currentNumber = -1;

            for (int i = 0; i < blub.Length; i++)
            {
                currentNumber = blub[i];

                if(!mostCommonElements.ContainsKey(currentNumber))
                {
                    mostCommonElements.Add(currentNumber, 0);
                }

                for (int j = 0; j < blub.Length; j++)
                {
                    if(currentNumber == blub[j])
                    {
                        mostCommonElements[currentNumber]++;
                    }
                }
            }
        }

        private static void fillArray(ref int[] blub, int len)
        {
            Random r = new Random();

            for (int index = 0; index < len; index++)
            {
                blub[index] = r.Next(1, 101);
            }
        }
    }
}