Data structures and abstract data types

Question 1

Define primitive data type and give an example

Answer 1

They can only contain one data value. e.g. Integer, Boolean, Real etc

Question 2

Define composite/compound data type and give an example

Answer 2

They’re built by combining primitive data types e.g. Records, Class

Question 3

Define data structures

Answer 3

A collection of data that is organised to allow efficient processing. This means a wide range of sorting algorithms can be used

Question 4

Define abstract data types

Answer 4

A conceptual model that describes how data is organised and which operations can be carried out from the perspective of an end user with no background knowledge

Question 5

How do static data structures deal with memory?

Answer 5

They reserve enough memory for a set amount of data established in advance. The structure can not be resized

Question 6

How are static data structures efficient and inefficient?

Answer 6

They’re very memory efficient as they can access elements directly by index.
They’re inefficient if the wrong amount of memory is allocated leading to wastage or errors

Question 7

How do dynamic data structures deal with memory?

Answer 7

The memory capacity is not fixed and the number of elements it can hold is only limited by the memory allocation for the whole program

Question 8

Name an advantage and disadvantage of dynamic data structures

Answer 8

Advantage is that the memory size is not pre set

A disadvantage is that elements can not be accessed directly- only by memory location which is sequential

Question 9

What is a memory heap?

Answer 9

The amount of memory allocated to a program at run time that data structures can access

Question 10

Definition of an array

Answer 10

A data structure that holds a number of elements of the same data type

Question 11

How are arrays declared & processed?

Answer 11

Declared under a single identifier and processed efficiently using iteration techniques

Question 12

How do arrays use indexes?

Answer 12

Each position is identified by an index, usually using zero-based indexing. Data is stored contiguously( next to each other) in main memory so each position is directly acessible

Question 13

Are the values in an array mutable?

Answer 13

Yes, they can be changed while the program is running

Question 14

What are the three steps to declaring a one dimensional array?

Answer 14

Create an identifier
Specify the data type of the elements
Specify the number of positions in the array

Question 15

What’s another name for a 2D array?

Answer 15

A Matrix

Question 16

What 2 values do you need to access an element in a 2D array?

Answer 16

A column index and a row index

Question 17

Define a record

Answer 17

A data structure which consists of a fixed number of variables called fields

Question 18

What does every field have to have?

Answer 18

A field name (Identifier) and a data type

Question 19

Name a simple way of storing data

Answer 19

Text files