Commit ce22aa3

@@ -1,6 +1,12 @@
 #!/usr/bin/env ruby
 require 'mathy'
 
+verifier = Mathy::Verification.new
+operations = [
+  Mathy::Addition.new(verifier),
+  Mathy::Subtraction.new(verifier)
+]
+
 console = Mathy::Console.new
 game = Mathy::Game.new(console)
-game.play(console.how_many_turns?, console.operation?)
+game.play(console.how_many_turns?, console.operation?(operations))

@@ -1,11 +1,18 @@
 module Mathy
   class Addition
+    attr_reader :key
+
     def initialize(verification)
       @verifier = verification
+      @key = "+"
     end
 
     def play_turn(x: rand(10), y: rand(20), correct_answer: x + y)
       @verifier.check_answer("#{x} + #{y} = ", correct_answer)
     end
+
+    def matches?(other_key)
+      key == other_key
+    end
   end
 end

@@ -9,15 +9,9 @@ module Mathy
       prompt?("how many questions do you want?").to_i
     end
 
-    def operation?(verifier = Verification.new)
-      case prompt?("choose operation? [+-]")
-      when "+"
-        Addition.new(verifier)
-      when "-"
-        Subtraction.new(verifier)
-      else
-        Addition.new(verifier)
-      end
+    def operation?(operations)
+      selection =  prompt?("choose operation? #{operations.map(&:key).flatten}")
+      operations.find { |operation| operation.matches?(selection) }
     end
 
     def prompt?(question)

@@ -1,11 +1,18 @@
 module Mathy
   class Subtraction
+    attr_reader :key
+
     def initialize(verification)
       @verifier = verification
+      @key = "-"
     end
 
     def play_turn(x: rand(10), y: rand(20), correct_answer: x - y)
       @verifier.check_answer("#{x} - #{y} = ", correct_answer)
     end
+
+    def matches?(other_key)
+      key == other_key
+    end
   end
 end