Data commit

Task/Playing-cards/C-sharp/playing-cards.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+
+public struct Card
+{
+    public Card(string rank, string suit) : this()
+    {
+        Rank = rank;
+        Suit = suit;
+    }
+
+    public string Rank { get; }
+    public string Suit { get; }
+
+    public override string ToString() => $"{Rank} of {Suit}";
+}
+
+public class Deck : IEnumerable<Card>
+{
+    static readonly string[] ranks = { "Two", "Three", "Four", "Five", "Six",
+        "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King", "Ace" };
+    static readonly string[] suits = { "Clubs", "Diamonds", "Hearts", "Spades" };
+    readonly List<Card> cards;
+
+    public Deck() {
+        cards = (from suit in suits
+                from rank in ranks
+                select new Card(rank, suit)).ToList();
+    }
+
+    public int Count => cards.Count;
+
+    public void Shuffle() {
+        // using Knuth Shuffle (see at http://rosettacode.org/wiki/Knuth_shuffle)
+        var random = new Random();
+        for (int i = 0; i < cards.Count; i++) {
+            int r = random.Next(i, cards.Count);
+            var temp = cards[i];
+            cards[i] = cards[r];
+            cards[r] = temp;
+        }
+    }
+
+    public Card Deal() {
+        int last = cards.Count - 1;
+        Card card = cards[last];
+        //Removing from the front will shift the other items back 1 spot,
+        //so that would be an O(n) operation. Removing from the back is O(1).
+        cards.RemoveAt(last);
+        return card;
+    }
+
+    public IEnumerator<Card> GetEnumerator() {
+        //Reverse enumeration of the list so that they are returned in the order they would be dealt.
+        //LINQ's Reverse() copies the entire list. Let's avoid that.
+        for (int i = cards.Count - 1; i >= 0; i--)
+            yield return cards[i];
+    }
+
+    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() => GetEnumerator();
+}