Leaves-Yasmin

.github/PULL_REQUEST_TEMPLATE

@@ -4,12 +4,25 @@ Thanks for doing some brain yoga. You are now submitting this assignment!
 ## Comprehension Questions
 |  Question 	|  Answer 	|
 |------------	| ---------	|
-|  What is an ADT?	|   	|
-|  Describe a Stack	|   	|
-|  What are the 5 methods in Stack and what does each do?	|   	|
-|  Describe a Queue	|   	|
-|  What are the 5 methods in Queue and what does each do?	|   	|
-|  What is the difference between implementing something and using something? | 	|
+|  What is an ADT?	| --> Abstract Data type (ADT) is a type (or class) for objects 
+  whose behaviour is defined by a set of value and a set of operations.  	|
+
+|  Describe a Stack	| --> A stack is an abstract data type, (Last in First out) that serves as a collection of elements, 
+   with two principal operations: push, which adds an element to the collection, and
+   pop, which removes the most recently added element that was not yet removed.  	|
+
+|  What are the 5 methods in Stack and what does each do?	| push : Pushes an element on the top of the stack.
+ pop : Removes and returns the top element of the stack. 
+ empty : It returns true if nothing is on the top of the stack ( if the stack is empty). Else, returns false.
+ peek : Returns the element on the top of the stack, but does not remove it.  	|
+
+|  Describe a Queue	| A Queue is an Abstract Data Structure which stores data and allows access in a First-In-First-Out order (FIFO)/last in last out.  	|
+
+|  What are the 5 methods in Queue and what does each do?	| enqueue: add an element to the rear of the queue
+dequeue: Remove & return the element from the front
+is_empty: returns true if the queue is empty   	|
+
+|  What is the difference between implementing something and using something? | Implementing something: is to build it and know the how it works. Using something: using existing code	|
 
 ## OPTIONAL JobSimulation
 |  Question 	|  Answer 	|

lib/queue.rb

@@ -2,30 +2,65 @@ class Queue
 
   def initialize
     # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(100)
+    @front = @back = -1
+    # @front = -1
+    # @back = -1
   end
 
   def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    if @front == -1 && @back == -1
+      @front = 0
+      @back = 1
+      @store[@front] = element
+    elsif @front == @back
+      #DECIDE
+      raise ArgumentError, "Queue is full!"
+    else
+      @store[@back] = element
+      @back = (@back + 1) % @store.length
+    end
   end
 
   def dequeue
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    if @front == @back
+      raise ArgumentError, "Queue is empty!"
+    end
+    if element = @store[@front]
+      @front = (@front + 1) % @store.length
+      return element
+    end
   end
 
   def front
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    return @store[@front]
   end
 
   def size
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    return @store.length
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    if @front == @back
+      return true
+    else
+      return false
+    end
   end
 
   def to_s
-    return @store.to_s
+    # return @store.to_s
+    queue = []
+    until @front == @back
+      queue << @store[@front]
+      @front = (@front + 1) % @store.length
+    end
+    return queue.to_s
   end
 end

lib/stack.rb

@@ -1,19 +1,26 @@
+require_relative "./linked_list"
+
 class Stack
   def initialize
     # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    @store = LinkedList.new
   end
 
   def push(element)
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    @store.add_last(element)
   end
 
   def pop
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    return nil if self.empty?
+    @store.remove_last
   end
 
   def empty?
-    raise NotImplementedError, "Not yet implemented"
+    # raise NotImplementedError, "Not yet implemented"
+    return @store.empty?
   end
 
   def to_s

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)
@@ -27,13 +25,11 @@
   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)
@@ -43,7 +39,6 @@
   end
 
   it "removes something from the Queue" do
-    skip
     q = Queue.new
     q.enqueue(5)
     removed = q.dequeue
@@ -52,7 +47,6 @@
   end
 
   it "removes the right something (LIFO)" do
-    skip
     q = Queue.new
     q.enqueue(5)
     q.enqueue(3)
@@ -63,7 +57,6 @@
   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 +68,6 @@
   end
 
   it "returns the front element in the Queue" do
-    skip
     q = Queue.new
     q.enqueue(40)
     q.enqueue(22)

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)