topic: data structures

Question 1

what is an array

Answer 1

a data structure that contains more than data item, they have to be the same data type
it is also a linear data structure as it allocates a contiguous part of memory for the purpose of storing that data

Question 2

what is the difference between an array and a list

Answer 2

an array is a static data structure- you cannot change its size once its been set up, only 1 data type
a list is dynamic, and can store more than 1 data type

Question 3

visuals for 2d arrays, 3d arrays, and 4d arrays

Answer 3

a table (rown, column)
a cube (height, length, depth)
multiple cubes (first index chooses the cube, height, length, depth)

Question 4

what is a record structure

Answer 4

composite data structure that groups related fields of different data types under one identifier
it represents a single fixed entity
a field is a variable

Question 5

what is special about fields, in record structures

Answer 5

each field can have different data types

Question 6

what are the 3 steps to use a record data structure

Answer 6

1. define record structure. what fields will it have?
2. declare a variable or array to use with the record structure
3. assign and retrieve data from the variable record

Question 7

give a list of linear data structures

Answer 7

arrays, records, lists (- linked lists, tuples), stacks, queues, hash table

Question 8

what is a static data structure
examples ..

Answer 8

when data structure are in a fixed size when structure is created
and the size cannot change at run-time
e.g. arrays.

Question 9

what is a dynamic data structure
examples..

Answer 9

a data structure thats size change during processing
it uses an area of memory called the heap

e.g. lists and linked lists

Question 10

what is the problem with a dynamic data structure
examples..

Answer 10

as the size can change it is possible for the structure to ‘overflow’ if it exceeds the maximum allowed memory
this means the system returns an error since the memory allocation has failed and the program should detect the failure

e.g. list, linked-list

Question 11

what are some dynamic data structures

Answer 11

lists and linked lists

Question 12

what is the heap

Answer 12

memory set aside for dynamic allocation like dynamic data structures, objects
space is allocated and deallocated as required

Question 13

what does immutable mean examples..

Answer 13

means the data structure does not change - static data / fixed size
elements cannot be added, removed or changed .e.g. tuples

Question 14

define data structure
what are the two types of data structures

Answer 14

a particular way of storing and organising related data in a way that utilises it in an efficient manner
-linear and non linear data structures

Question 15

define a linear data structure

Answer 15

the elements are stored sequentially, and the elements are connected to the previous and the next element, so they can be traversed or accessed in a single run
the implementation of linear data structures is easier as the elements are sequentially organized in memory

Question 16

define non linear data structure

Answer 16

when data elements are not arranged in a contiguous manner, since the arrangement is nonsequential, so the data elements cannot be traversed or accessed in a single run
in the non-linear data structure, an element can be connected to more than two elements

Question 17

what are 3 traits of tuples

Answer 17

• an immutable list which cannot be changed (size or contents) during processing
• unlike arrays, tuples can have different datatypes
• they’re good for data which does not change in size or content .e.g. days of the week or months of the year

Question 18

what are 4 traits of records

Answer 18

• they’re a group or collection of related fields under a single identifier
• each field (variable) can have a different data type (unlike arrays)
• used in conjunction with arrays or lists e.g. a list of students
• to access each field in the structure, use dot notation as shown right

Question 19

what are 3 traits of arrays

Answer 19

• mutable (meaning individual elements stored in them can be changed or replaced)
• they are typically static (meaning their total size/length is fixed upon declaration)
• can only store one data type