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Stacks and Queues

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Comprehension Questions

Question	Answer
What is an ADT?	an "Abstract Data Type" usually implemented in a class for an object to define the kinds of values the object takes in, as well as specify the operations performed on said data, and their outcomes.
Describe a Stack	an ADT! it's LIFO -> Last in, first out. We can only access the top element of a stack at a time.
What are the 5 methods in Stack and what does each do?	we used push, pop, & empty, to add an element, remove an element from the top, and empty to determine if it was empty or not. There is also usually an empty method similar to the empty? method in our queue class and often a peek method to return the top of the stack and sometimes a search method.
Describe a Queue	A queue is usually FIFO -> First in, first out. It’s the data structure that simulates waiting in line.
What are the 5 methods in Queue and what does each do?	enqueue, (or put), to add data into the queue, dequeue ( or get), to remove and return an item from the queue, size (or length) to return the amount of data in the queue, empty? to determine if there is any data in the queue, and usually there is a method to determine if the queue is full or not, which was handled originally with an exception class in our put or enqueue method.
What is the difference between implementing something and using something?	when you’ve implemented the thing, it’s ready for use. This is the thing, it is ready to hold and manipulate data but it isn’t programmatically changing any data until someone uses the ADT (thing) by passing in data.