4.2.1 FoDS (Data strutures and abstract data types)

Question 1

What is meant by the term data structure

Answer 1

A way of organising and storing data in a computer so that it can be accessed and modified

Question 2

What is meant by an abstract data type

Answer 2

a conceptual model that describes how data is organised and which operations can be carried out on the data (e.g. insert, delete) from the perspective of an end user who does not need to know how this is implemented.

Question 3

What is meant by a static data structure

Answer 3

A data structure that reserves memory for a set amount of data established by the programmer

Question 4

What are the features of static data structures

Answer 4

• Fixed in size making them memory inefficient
• They can only contain one type of data
• The contents can be changed

Question 5

What is meant by a dynamic data structure

Answer 5

• A data structure that can increase or decrease in capacity

Question 6

What are the features of dynamic data structures

Answer 6

• Changeable capacity
• No indexing so elements cannot easily be accessed (only through a sequential pass through the list)
• Capacity is reliant on the memor allocated to the program

Question 7

What is meant by an array

Answer 7

A static data structure that represents a collection of the same type of data under a shared common name

Question 8

What are 1, 2, and 3D array useful for

Answer 8

1- A vector
2- Matrix
3+ - A set of elements that are indexed by a tuple of n intergers

Question 9

What is a record

Answer 9

A grouped collection of related data containing fields under a single identifier

Question 10

What are binary files

Answer 10

Files that store data in binary, and follow a known format that can be read by a program

Question 11

What are binary files used for and why

Answer 11

• Image and videos
• Music
• programs
  As it is more compact and efficient for storage and speed

Question 12

What are text files used for and why

Answer 12

• Human readable documents
  Because they are easy to understand and share

Question 13

What abstract data structures can be implemented using arrays and linked lists

Answer 13

• Queues
• Stacks

Question 14

What methods can be used to implement graphs

Answer 14

• Arrays that are implemented as matrices

Question 15

What methods can be used to implement trees

Answer 15

• OOP, that objectifies nodess which has pointers to its children

Question 16

What methods can be used to implement Hash Tables and Dictionaries

Answer 16

• array of linked lists

Question 17

What methods can be used to implement Vectors

Answer 17

• An Arraylist

Question 18

What are the advantages of static data structures

Answer 18

• Makes efficient use of memory as data structure only uses as much memory as it needs

Question 19

What are the disadvantages of static data structures

Answer 19

• It runs the risk of overflow when the memory used exeeds the allowed limit
• Harder to program with as you need to monitor the size and location of the data structure at all times

Question 20

What are the advantages of dynamic data structures

Answer 20

-Easier to program with as there is no requirement to check on the size of the data structure at any point before access
-Memory allocation is fixed which means there will be no modifying issues (overflow or underflow)

Question 21

What are the disadvantages of dynamic data structures

Answer 21

• Can be very inefficient as memory for the data structure is set aside at the start of the program but might not be utilised