Finished stacks questions and tests passing, updated methods

Author: criacuervos

lib/queue.rb

@@ -7,25 +7,36 @@ def initialize
   end
 
   def enqueue(element)
+    #Circular buffer method
     #Check if queue is empty
     if @front == -1 && @back == -1
       @front = 0
       @back = 1 
     end 
-    #Check if queue is full
-    if @front == @back
-      #Decide what to do if circular buffer is full 
-    end 
 
-    @store(@back) = element 
-    @back += 1 
+    #Check if queue is full
+    if ((@back + 1) % @store.length) == @front
+      raise ArgumentError.new("Queue is full!")
+    end
 
-    #Make it wrap around when it reaches the end 
+    @store[@back] = element
+    #Make it wrap around when it reaches the end & use modulo to not go over the end
     @back = (@back + 1) % @store.length
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    if @front == @back
+      raise ArgumentError.new("Queue is empty!")
+    end
+    
+    #Store the current first element in a temp
+    temp = @store[@front]
+    #Make the front element nil 
+    @store[@front] = nil
+
+    @front = (@front + 1) % @store.length
+    
+    return temp
   end
 
   def front

lib/stack.rb

@@ -1,19 +1,23 @@
+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)
+    return @store
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    return @store.remove_last if @store.get_first != nil 
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    if @store.get_first == nil
+      return true 
+    end
   end
 
   def to_s

test/stack_test.rb

@@ -17,7 +17,6 @@
   end
 
   it "pushes multiple somethings onto a Stack" do
-    skip
     s = Stack.new
     s.push(10)
     s.push(20)
@@ -26,13 +25,11 @@
   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 +38,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     s = Stack.new
     s.push(5)
     s.push(3)