Leaves-Yasmin

[YasminM11]

Stacks and Queues

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Comprehension Questions

Question	Answer
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
Did you include a sample run of your code as a comment?

[CheezItMan]

Nice work. One minor issue with the Queue, but otherwise excellent job. Take a look at my comments and let me know if you have questions.

[CheezItMan]

👍

[CheezItMan]

The problem here is determining if the queue is empty or full because in either case front would be equal to back.

So

Suggested change

	if element = @store[@front]
	@front = (@front + 1) % @store.length
	return element
	if element = @store[@front]
	@front = (@front + 1) % @store.length
	@front = @back = -1 if @front == @back
	return element

[CheezItMan]

This only gives you the length of the internal storage, not the size of the queue.

[CheezItMan]

Suggested change

	if @front == @back
	return true
	else
	return false
	end
	return @front == @back

[CheezItMan]

👍