1.4.2 - Data Structures

Question 1

What is a stack?

Answer 1

A last in first out (LIFO) data structure.

Question 2

What is are 2 applications of a stack?

Answer 2

The back button on a web browser and used to store information of active subroutines.

Question 3

What are 5 operations of a stack and what do they do?

Answer 3

.push(item) - Adds a new item to the top of a stack.
.pop() - Removes and returns the top item from the stack.
.peek() - Returns the top item from the stack but does not remove it.
.isEmpty() - Returns a boolean value of whether the stack is empty.
.isFull() - Returns a boolean value of where the stack is full.

Question 4

How does overflow occur in a stack?

Answer 4

A stack will always have a maximum size because memory cannot grow indefinitely therefore, if you try to push an item to a full stack overflow will occur.

Question 5

How does underflow occur in a stack?

Answer 5

When you try and pop an item from an empty stack.

Question 6

What is the stack pointer for this stack [].

Answer 6

-1

Question 7

What is the stack pointer for this stack [‘Blue’].

Answer 7

0

Question 8

What is a queue?

Answer 8

A first in first out (FIFO) data structure?

Question 9

What operations can be performed on a queue and what do they do?

Answer 9

.enQueue(item) - Add a new item to the end of the queue.
.deQueue() - Remove the front item from the queue and return it.
.isEmpty()
.isFull()

Question 10

What is a list?

Answer 10

An abstract data type with a number of items where the same item can occur more than once.

Question 11

What are 9 operations on a list and what do they do?

Answer 11

.isEmpty()
.append(item)
.remove(item)
.search(item) - Returns Boolean
.length()
.index(item) - Returns the index of an item
.insert(index, item)
.pop(index)

Question 12

What is a graph?

Answer 12

A set of vertices or nodes that are connected by edges or arcs.