Program.cs

using System;
using System.Collections.Generic;

namespace AllCardsOnDeckCS
{
    class Program
    {
        static void Main(string[] args)
        {
            var deck = new List<string>() {
                "Ace of Hearts" ,
                "2 of Hearts" ,
                "3 of Hearts" ,
                "4 of Hearts" ,
                "5 of Hearts" ,
                "6 of Hearts" ,
                "7 of Hearts" ,
                "8 or Hearts" ,
                "9 of Hearts" ,
                "10 of Hearts" ,
                "Jack of Hearts" ,
                "Queen of Hearts" ,
                "King of Hearts" ,

                "Ace of Spades" ,
                "2 of Spades" ,
                "3 of Spades" ,
                "4 of Spades" ,
                "5 of Spades" ,
                "6 of Spades" ,
                "7 of Spades" ,
                "8 or Spades" ,
                "9 of Spades" ,
                "10 of Spades" ,
                "Jack of Spades" ,
                "Queen of Spades" ,
                "King of Spades" ,

                "Ace of Clubs" ,
                "2 of Clubs" ,
                "3 of Clubs" ,
                "4 of Clubs" ,
                "5 of Clubs" ,
                "6 of Clubs" ,
                "7 of Clubs" ,
                "8 or Clubs" ,
                "9 of Clubs" ,
                "10 of Clubs" ,
                "Jack of Clubs" ,
                "Queen of Clubs" ,
                "King of Clubs" ,

                "Ace of Diamonds" ,
                "2 of Diamonds" ,
                "3 of Diamonds" ,
                "4 of Diamonds" ,
                "5 of Diamonds" ,
                "6 of Diamonds" ,
                "7 of Diamonds" ,
                "8 of Diamonds" ,
                "9 of Diamonds" ,
                "10 of Diamonds" ,
                "Jack of Diamonds" ,
                "Queen of Diamonds" ,
                "King of Diamonds" };

            var numberOfCards = deck.Count;
            // var rightIndex = numberOfCards - 1;

            for (var rightIndex = numberOfCards - 1; rightIndex >= 1; rightIndex--)
            {
                var randomNumberGenerator = new Random();
                var leftIndex = randomNumberGenerator.Next(rightIndex);

                var leftCard = deck[leftIndex];
                var rightCard = deck[rightIndex];

                deck[rightIndex] = leftCard;
                deck[leftIndex] = rightCard;

            }

            var firstCard = deck[0];
            var secondCard = deck[1];
            Console.WriteLine($"Finished shuffling! Your cards are {firstCard} and {secondCard}!");

        }
    }
}