diff --git a/lib/queue.rb b/lib/queue.rb
index 828217c6..81f0b6fb 100644
--- a/lib/queue.rb
+++ b/lib/queue.rb
@@ -1,16 +1,35 @@
-class Queue
 
+class Queue
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(10)
+    @front = @back = -1
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1 && @back == -1
+      @front = 0
+      @back = 1
+    end
+    if @front == @back
+      raise ArgumenetError
+    end
+    @store[@back] = element
+    @back = (@back + 1) % @store.length
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1
+      raise ArgumenetError
+    elsif @front == @back
+      @front = -1
+      @back = -1
+    else
+      first = @store[@front]
+      @store[@front] = nil
+      @front = (@front + 1) % @store.length
+    end
+   
+    return first
   end
 
   def front
@@ -22,10 +41,10 @@ def size
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return true if @front = -1 && @back - 1
   end
 
   def to_s
-    return @store.to_s
+    return @store[@front + 1...@back].to_s
   end
 end
diff --git a/lib/stack.rb b/lib/stack.rb
index cfc6ef0f..d9bc9026 100644
--- a/lib/stack.rb
+++ b/lib/stack.rb
@@ -1,19 +1,19 @@
+require_relative './linked_list.rb'
 class Stack
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new()
   end
 
   def push(element)
-    raise NotImplementedError, "Not yet implemented"
+    @store.add_last(element)
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    @store.remove_last()
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    @store.empty?
   end
 
   def to_s
diff --git a/test/queue_test.rb b/test/queue_test.rb
index 66372e26..17d3dc68 100644
--- a/test/queue_test.rb
+++ b/test/queue_test.rb
@@ -11,14 +11,12 @@
   end
 
   it "adds something to an empty Queue" do
-    skip
     q = Queue.new
     q.enqueue(10)
     expect(q.to_s).must_equal "[10]"
   end
 
   it "adds multiple somethings to a Queue" do
-    skip
     q = Queue.new
     q.enqueue(10)
     q.enqueue(20)
@@ -27,23 +25,24 @@
   end
 
   it "starts the size of a Queue at 0" do
-    skip
+
     q = Queue.new
     q.empty?.must_equal true
   end
 
   it "a Queue is empty after removing all the elements" do
-    skip
+
     q = Queue.new
     q.enqueue(5)
     q.enqueue(6)
+  
     expect( expect(q.dequeue) ).must_equal 5
     expect( expect(q.dequeue) ).must_equal 6
     expect(q.empty?).must_equal true
   end
 
   it "removes something from the Queue" do
-    skip
+  
     q = Queue.new
     q.enqueue(5)
     removed = q.dequeue
@@ -52,7 +51,7 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
+
     q = Queue.new
     q.enqueue(5)
     q.enqueue(3)
@@ -63,7 +62,7 @@
   end
 
   it "properly adjusts the size with enqueueing and dequeueing" do
-    skip
+
     q = Queue.new
     q.empty?.must_equal true
     q.enqueue(-1)
@@ -75,7 +74,7 @@
   end
 
   it "returns the front element in the Queue" do
-    skip
+
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)
@@ -84,6 +83,7 @@
     expect(q.dequeue).must_equal 22
   end
   it "works for a large Queue" do
+
     q = Queue.new
     q.enqueue(10)
     q.enqueue(20)
@@ -102,7 +102,6 @@
     q.enqueue(130)
     q.enqueue(140)
     q.enqueue(150)
-    q.enqueue(150)
     q.enqueue(160)
     q.enqueue(170)
     q.enqueue(180)
@@ -111,6 +110,6 @@
     q.enqueue(210)
     q.dequeue
 
-    expect(q.to_s).must_equal('[30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200]')
+    expect(q.to_s).must_equal('[30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200,210]')
   end
 end
diff --git a/test/stack_test.rb b/test/stack_test.rb
index df5046c8..2cf9d5d9 100644
--- a/test/stack_test.rb
+++ b/test/stack_test.rb
@@ -10,14 +10,12 @@
   end
 
   it "pushes something onto a empty Stack" do
-    skip
     s = Stack.new
     s.push(10)
     s.to_s.must_equal "[10]"
   end
 
   it "pushes multiple somethings onto a Stack" do
-    skip
     s = Stack.new
     s.push(10)
     s.push(20)
@@ -26,13 +24,11 @@
   end
 
   it "starts the stack empty" do
-    skip
     s = Stack.new
     s.empty?.must_equal true
   end
 
   it "removes something from the stack" do
-    skip
     s = Stack.new
     s.push(5)
     removed = s.pop
@@ -41,7 +37,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     s = Stack.new
     s.push(5)
     s.push(3)