diff --git a/lib/queue.rb b/lib/queue.rb
index 828217c6..9336dc5c 100644
--- a/lib/queue.rb
+++ b/lib/queue.rb
@@ -1,16 +1,37 @@
+# QUEUE_SIZE = 20
 class Queue
-
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(20)
+    @queue_size = 20
+    @front = @rear = -1
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    if @front == -1 #Q is empty
+      @front = 0
+      @rear = 1
+      @store[@front] = element
+    elsif @front == @rear
+      raise ArgumentError, "Q FULL"
+    else #not empty
+      @store[@rear] = element
+      @rear = (@rear + 1) % @queue_size
+    end
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1
+      reise ArgumentError, "Queue empty"
+    else
+      element = @store[@front]
+      @front = (@front + 1) % @queue_size
+      if @front == @rear
+        @front = -1
+        @rear = -1
+      end
+    end
+    return element
   end
 
   def front
@@ -22,10 +43,21 @@ def size
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1
+      return true
+    else
+      return false
+    end
   end
 
   def to_s
-    return @store.to_s
+    list = []
+    current = @front
+    while current != @rear
+      list << @store[current]
+      current = (current + 1) % @queue_size
+    end
+    return list.to_s
   end
 end
+
diff --git a/lib/stack.rb b/lib/stack.rb
index cfc6ef0f..0ad4f025 100644
--- a/lib/stack.rb
+++ b/lib/stack.rb
@@ -1,22 +1,29 @@
+require_relative "linked_list"
+
 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"
+    last = @store.get_last()
+    if last == nil
+      return true
+    else
+      return false
+    end
   end
 
   def to_s
     return @store.to_s
   end
 end
+
diff --git a/test/queue_test.rb b/test/queue_test.rb
index 9b616a30..5cef322b 100644
--- a/test/queue_test.rb
+++ b/test/queue_test.rb
@@ -11,14 +11,14 @@
   end
 
   it "adds something to an empty Queue" do
-    skip
+    
     q = Queue.new
     q.enqueue(10)
     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)
@@ -27,7 +27,7 @@
   end
 
   it "starts the size of a Queue at 0" do
-    skip
+    
     q = Queue.new
     q.empty?.must_equal true
   end
@@ -42,7 +42,7 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
+    
     q = Queue.new
     q.enqueue(5)
     q.enqueue(3)
@@ -53,7 +53,7 @@
   end
 
   it "properly adjusts the size with enqueueing and dequeueing" do
-    skip
+    
     q = Queue.new
     q.empty?.must_equal true
     q.enqueue(-1)
@@ -65,7 +65,7 @@
   end
 
   it "returns the front element in the Queue" do
-    skip
+    
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)
diff --git a/test/stack_test.rb b/test/stack_test.rb
index df5046c8..a790a3d0 100644
--- a/test/stack_test.rb
+++ b/test/stack_test.rb
@@ -10,14 +10,14 @@
   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 +26,13 @@
   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 +41,7 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
+    
     s = Stack.new
     s.push(5)
     s.push(3)