Commit 497c8f2

@@ -0,0 +1,96 @@
+class Console
+  def greet
+    clear_screen
+    prompt?('what is your name?')
+  end
+
+  def how_many_turns?
+    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
+  end
+
+  def prompt?(question)
+    puts question
+    gets.strip
+  end
+
+  private
+
+  def clear_screen
+    puts "\e[H\e[2J"
+  end
+end
+
+class Verification
+  def check_answer(question, correct_answer)
+    puts ""
+    print question
+    answer = gets
+    if answer.to_i == correct_answer
+      print "Correct!"
+      return true
+    end
+    print "The correct answer is #{correct_answer}."
+    false
+  end
+
+end
+
+class Addition
+  def initialize(verification)
+    @verifier = verification
+  end
+
+  def play_turn(x: rand(10), y: rand(20), correct_answer: x + y)
+    @verifier.check_answer("#{x} + #{y} = ", correct_answer)
+  end
+end
+
+class Subtraction
+  def initialize(verification)
+    @verifier = verification
+  end
+
+  def play_turn(x: rand(10), y: rand(20), correct_answer: x - y)
+    @verifier.check_answer("#{x} - #{y} = ", correct_answer)
+  end
+end
+
+class Game
+  def initialize(console, score = 0)
+    @name = console.greet
+    @score = score
+  end
+
+  def play(games_to_play = 2, operation)
+    games_to_play.times do
+      @score += 1 if operation.play_turn(x: rand(10), y: rand(20))
+    end
+
+    display_results(@name, @score, games_to_play)
+  end
+
+  private
+
+  def display_results(name, score, games_to_play)
+    puts ""
+    puts "+++++++++++++++++++++++++++++++++++"
+    puts "You got #{score}/#{games_to_play}."
+    puts "Good bye #{name}"
+    puts "+++++++++++++++++++++++++++++++++++"
+  end
+end
+
+console = Console.new
+game = Game.new(console)
+game.play(console.how_many_turns?, console.operation?)