Here I wrote code for finding repeated (Duplicate numbers) numbers using lambda expression in c#.

I know its easy but surely it will for beginners.

public static void repeated()

{

int count=0;

int[] data = { 1, 2, 3, 4, 5, 6, 7, 8, 5, 9, 8, 10, 11, 12, 10, 13, 14, 15, 12, 16, 17, 18, 15, 19, 20 };

var res = data.GroupBy(t => t);

foreach(var t in res)

{

if (t.Count() > 1)

{

Console.WriteLine("The number " + t.Key + " repeated " + t.Count() + " times");

}

}

}