画面表示用に外応するスート、11をJ（ジャック）のように変換するメソッドを追加した

card.rb

@@ -1,12 +1,31 @@
 class Card
-  SUITS = [:♠︎, :♣︎, :♡, :♢]
+  SUITS = [:spade, :heart, :diamond, :clover]
+
+  MARK = {
+    spade: "♠",
+    heart: "♡",
+    diamond: "♢",
+    clover: "♣",
+    1 => "A",
+    11 => "J",
+    12 => "Q",
+    13 => "K"
+  }
 
   def initialize(suit, num)
     @num = num
     @suit = suit
   end
 
   def show
-    @suit.to_s + @num.to_s
+    corresponding_mark(@suit) + corresponding_mark(@num)
+  end
+
+  def corresponding_mark(sym)
+    if MARK[sym]
+      return MARK[sym]
+    else
+      return sym.to_s
+    end
   end
 end