Fire - Jing

lib/queue.rb

@@ -1,31 +1,52 @@
 class Queue
 
+  MAX_SIZE = 20
+
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(MAX_SIZE)
+    @head = @tail = 0
+    @size = 0
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    if @size == MAX_SIZE
+      raise StandardError, "Queue already reached its max size."
+    end
+    @store[@tail] = element
+    @tail = (@tail + 1) % MAX_SIZE
+    @size += 1
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    result = front
+    @store[@head] = nil
+    @head = (@head + 1) % MAX_SIZE
+    @size -= 1
+    return result
   end
 
   def front
-    raise NotImplementedError, "Not yet implemented"
+    if empty?
+      raise StandardError, "Queue is empty."
+    end
+    return @store[@head]
   end
 
   def size
-    raise NotImplementedError, "Not yet implemented"
+    return @size
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return @size == 0
   end
 
   def to_s
-    return @store.to_s
+    if empty?
+      return ""
+    elsif @head < @tail
+      return @store[@head...@tail].to_s
+    else
+      return @store[@head..].concat(@store[0...@tail]).to_s
+    end
   end
 end

lib/stack.rb

@@ -1,19 +1,21 @@
+require_relative './linked_list.rb'
+
 class Stack
   def initialize
-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new
+    @head = nil
   end
 
   def push(element)
-    raise NotImplementedError, "Not yet implemented"
+    @store.add_first(element)
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    @store.remove_first
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    return @head.nil?
   end
 
   def to_s

test/queue_test.rb

@@ -73,7 +73,7 @@
     expect(q.empty?).must_equal true
   end
 
-  it "returns the front element in the Queue" do
+  it "returns the element in the Queue" do
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)