using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

            int[] myArr = new int[] { 10, 5, 5, 3, 3, 3 };

​

            var numbersThatAreDuplicates = myArr.GroupBy(x => x).Where(x => x.Count() > 1).Select(x => new { number = x.Key, countOfNumber = x.Count()}).ToList();

​

            Console.WriteLine("There are {0} repeating values in the array.", numbersThatAreDuplicates.Count);

            foreach (var item in numbersThatAreDuplicates)

            {

                Console.WriteLine(item.number + " repeats itself " + item.countOfNumber + " times.");

            } 

    }

}

​

​