Leaves - Samantha

lib/queue.rb

@@ -1,31 +1,61 @@
 class Queue
-
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(30)
+    @front = @back = -1
   end
-
+  
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    # queue is empty
+    if @front == -1 && @back == -1
+      @front = 0
+      @back = 1
+      @store[@front] = element
+
+    elsif @front == @back
+      #queue is full
+      raise ArgumentError, "Queue is full"
+
+    else      
+      @store[@back] = element
+      @back = (@back + 1) % @store.length
+    end
   end
-
+  
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == -1
+      raise ArgumentError, "Queue is empty"
+    end  
+
+    removed = @store[@front]
+    @front = (@front + 1) % @store.length  
+
+    if @front == @back
+      @front = @back = -1
+    end 
+
+    return removed
   end
-
+  
   def front
-    raise NotImplementedError, "Not yet implemented"
+    return @store[@front]
   end
-
+  
   def size
-    raise NotImplementedError, "Not yet implemented"
+    return @store[@front...@back].length
   end
-
+  
   def empty?
-    raise NotImplementedError, "Not yet implemented"
-  end
-
+    return @front == -1
+  end 
+  
   def to_s
-    return @store.to_s
+    list = []
+    current = @front
+
+    while current != @back
+      list << @store[current]
+      current = (current + 1) % @store.length
+    end
+    return list.to_s
   end
-end
+end 

lib/stack.rb

@@ -1,21 +1,25 @@
+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"
+    return nil if self.empty?
+    element = @store.remove_last
+
+    return element
   end
-
+  
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return @store.empty?
   end
-
+  
   def to_s
     return @store.to_s
   end

test/queue_test.rb

@@ -7,72 +7,66 @@
 describe "Test Queue Implementation" do
   it "creates a Queue" do
     q = Queue.new
-    q.class.must_equal Queue
+    _(q.class).must_equal Queue
   end
-
+  
   it "adds something to an empty Queue" do
-    skip
     q = Queue.new
     q.enqueue(10)
-    q.to_s.must_equal "[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)
     q.enqueue(30)
-    q.to_s.must_equal "[10, 20, 30]"
+    _(q.to_s).must_equal "[10, 20, 30]"
   end
-
+  
   it "starts the size of a Queue at 0" do
-    skip
     q = Queue.new
-    q.empty?.must_equal true
+    _(q.empty?).must_equal true
   end
-
+  
   it "removes something from the Queue" do
-    skip
     q = Queue.new
     q.enqueue(5)
     removed = q.dequeue
-    removed.must_equal 5
-    q.empty?.must_equal true
+    _(removed).must_equal 5
+    _(q.empty?).must_equal true
   end
-
+  
   it "removes the right something (LIFO)" do
-    skip
     q = Queue.new
     q.enqueue(5)
     q.enqueue(3)
     q.enqueue(7)
     removed = q.dequeue
-    removed.must_equal 5
-    q.to_s.must_equal "[3, 7]"
+    _(removed).must_equal 5
+    _(q.to_s).must_equal "[3, 7]"
   end
-
+  
   it "properly adjusts the size with enqueueing and dequeueing" do
-    skip
     q = Queue.new
-    q.empty?.must_equal true
+    _(q.empty?).must_equal true
     q.enqueue(-1)
     q.enqueue(-60)
-    q.empty?.must_equal false
+    _(q.empty?).must_equal false
     q.dequeue
     q.dequeue
-    q.empty?.must_equal true
+    _(q.empty?).must_equal true
   end
-
+  
   it "returns the front element in the Queue" do
-    skip
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)
     q.enqueue(3)
     q.dequeue
     expect(q.dequeue).must_equal 22
   end
+
   it "works for a large Queue" do
     q = Queue.new
     q.enqueue(10)
@@ -92,15 +86,17 @@
     q.enqueue(130)
     q.enqueue(140)
     q.enqueue(150)
-    q.enqueue(150)
     q.enqueue(160)
     q.enqueue(170)
     q.enqueue(180)
     q.enqueue(190)
     q.enqueue(200)
     q.enqueue(210)
+    q.enqueue(220)
+    q.enqueue(230)
+    q.enqueue(240)
     q.dequeue
-
+    
     expect(q.to_s).must_equal('[40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240]')
   end
 end

test/stack_test.rb

@@ -6,48 +6,43 @@
 describe "Test Stack Implementation" do
   it "creates a Stack" do
     s = Stack.new
-    s.class.must_equal Stack
+    _(s.class).must_equal Stack
   end
-
+  
   it "pushes something onto a empty Stack" do
-    skip
     s = Stack.new
     s.push(10)
-    s.to_s.must_equal "[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)
     s.push(30)
-    s.to_s.must_equal "[10, 20, 30]"
+    _(s.to_s).must_equal "[10, 20, 30]"
   end
-
+  
   it "starts the stack empty" do
-    skip
     s = Stack.new
-    s.empty?.must_equal true
+    _(s.empty?).must_equal true
   end
-
+  
   it "removes something from the stack" do
-    skip
     s = Stack.new
     s.push(5)
     removed = s.pop
-    removed.must_equal 5
-    s.empty?.must_equal true
+    _(removed).must_equal 5
+    _(s.empty?).must_equal true
   end
-
+  
   it "removes the right something (LIFO)" do
-    skip
     s = Stack.new
     s.push(5)
     s.push(3)
     s.push(7)
     removed = s.pop
-    removed.must_equal 7
-    s.to_s.must_equal "[5, 3]"
+    _(removed).must_equal 7
+    _(s.to_s).must_equal "[5, 3]"
   end
-end
+end