2c

Question 1

Define abstraction

Answer 1

Process of removing excessive details to arrive at a representation of a problem that consists of only the key features. Often involves analysing what is relevant to a given scenario and simplifying a problem based on this information (representational abstraction)

Question 2

What is abstraction by generalisation

Answer 2

Process of removing excessive details to arrive at a representation of a problem that consists of only the key features. Often involves analysing what is relevant to a given scenario and simplifying a problem based on this information (representational abstraction)

Question 3

Define data abstraction

Answer 3

Details about how data is being stored are hidden. E.g stacks and queues

Question 4

What is the need of abstraction

Answer 4

Allows non experts to make use of a range of systems or models by hiding information that is too complex or irrelevant to the systems purpose
Enables more efficient software design
Reduces time spent on projects
Prevents unnecessarily large program

Question 5

Define thinking ahead

Answer 5

Thinking about the different components of a problem and how to handle them in the best way possible
Means designing strategies for programs is easier and intuitive to use

Question 6

Define preconditions

Answer 6

Requirements which must be met before a program can be executed
Specifying preconditions means subroutine can safely expect the arguments passed to certain criteria
Reduces length and complexity of code
Saves time needed to debug and maintain a longer program
Makes subroutines more reusable

Question 7

What are libraries

Answer 7

Contain commonly used functions for reuse, including queues, stacks, classes and subroutines

Question 8

Define decomposition

Answer 8

Breaking down a complex problem or system into smaller parts that are more manageable and easier to understand.

Question 9

What are the advantages of reusable components

Answer 9

More reliable
Already been tested
Saves money, time and resources
Can be reused in future projects (- compatibility issues)

Question 10

Define thinking procedurally

Answer 10

Large complex problem is continually broken down into smaller subproblems.
Makes project easier to manage and can be divided between a group of people

Question 11

Define paradigm

Answer 11

The approach used when developing a piece of software

Question 12

Define sequence

Answer 12

Code is executed line by line from top to bottom

Question 13

Define branching

Answer 13

Particular block of code is run if a specific condition is met

Question 14

Define iteration

Answer 14

Count controlled (block of code executed certain number of times)
Condition controlled (block of code is executed while a condition is met)

Question 15

Define scope

Answer 15

Section of code in which the variable can be accessed

Question 16

Define local variable

Answer 16

Can only be accessed within the subroutine in which they were defined
Deleted once subroutine ends
Ensure subroutines are self contained

Question 17

Define global variables

Answer 17

Accessed across the whole program
Danger of being unintentionally edited
Not deleted until program terminates, requires more memory

Question 18

Define modular programming

Answer 18

Technique used to split large, complex programs into smaller, self contained modules
Easier to divide tasks between a team
Each component can be dealt with individually
Improves reusability

Question 19

Examples of modularity

Answer 19

Breaking down problem into sub problems
Functions and procedures
Passing by value
Giving address of parameter to subroutine

Question 20

Define IDE

Answer 20

Program that provides a set of tools to make it easier for programmers to write, develop and debug code

Question 21

List features of IDE

Answer 21

Stepping
Variable watch
Breakpoint
Source code editor
Debugging tools

Question 22

List stages in the software development cycle (SDLC)

Answer 22

Analysis
Design
Development
Testing
Implementation
Evaluation
Maintenance

Question 23

Explain waterfall lice cycle

Answer 23

Stages are completed in sequence
Clear structure
To make change all stages must be revisited
Low user involvement
Lack flexibility
No risk analysis

Question 24

Explain agile methodologies

Answer 24

Aim to improve flexibility
Adapt quickly to user requirements
Different sections developed in parallel
Working prototype delivered early on
Less focus on documentation
High user satisfaction

Question 25

Explain extreme programming

Answer 25

Example of agile model High quality and highly usable software Programmers work no more than 40hrs per week Hard to produce high quality documentation

Question 26

Explain spiral model

Answer 26

Manages high risk projects Four stages: Analysing requirements Pinpointing and mitigating risks Development, testing and implementation Evaluating to inform the next iteration of Project terminated if too risky Specialist risk accessor hired Lack of focus on code efficiency

Question 27

Define RAD

Answer 27

Iterative methodology User requirements gathered using focus group Incomplete version given to user by trial User feedback used to generate improved prototype Final prototype matches user requirements fully Used when user requirements are incomplete or unclear Code may be inefficient Fast pace Late changes may reduce code quality

Question 28

Define algorithm

Answer 28

Set of instructions used to solve a problem

Question 29

Qualities of a good algorithm

Answer 29

Clearly defined inputs Valid output for defined input Able to deal with invalid inputs Must always reach a stopping condition Well do documented Well commented

Question 30

Define alpha testing

Answer 30

Carried out in house by software development teams Bugs are pinpointed and fixes

Question 31

Define beta testing

Answer 31

Carried out by end users Feedback from users informs next stage of development

Question 32

Define white box testing

Answer 32

Carried out by software development teams Internal structure of program is recognised All possible routes through program are tested

Question 33

Define black box testing

Answer 33

Testers are not aware of internal structure of the software Test plan traces through inputs and outputs

Question 34

Purpose of a trace table

Answer 34

Records when and which variables are updated

Question 35

Explain time complexity

Answer 35

Time taken to solve particular problem Measured with bi-o notation to show effectiveness

Question 36

Notation for constant time complexity

Answer 36

0(1) Time taken for algorithm independent from number of elements inputted

Question 37

Notation for linear time complexity

Answer 37

0(n) Time taken is directly proportional to the number of elements inputted

Question 38

Define space complexity

Answer 38

Amount of storage an algorithm takes

Question 39

Define algorithm

Answer 39

Series of steps that complete a task

Question 40

How to reduce space complexity on an algorithm

Answer 40

Perform all of the changes on the original pieces of data

Question 41

How to reduce time complexity on an algorithm

Answer 41

Reduce the number of embedded for loops as possible

Question 42

Explain a linear search algorithm

Answer 42

Traverses through every item one at a time until it finds the item it is earthing for

Question 43

Explain binary search algorithm

Answer 43

Divides and conquers Only applied on sorted data

Question 44

Explain bubble sort algorithm

Answer 44

Passes through the list evaluating pairs of items and ensuring the larger value is above the smaller value

Question 45

Explain what a stack is

Answer 45

First in last out data structure

Question 46

How to check size of stack

Answer 46

size()

Question 47

How to check if stack is empty

Answer 47

isEmpty()

Question 48

How to return top element of stack

Answer 48

peek()

Question 49

How to add to stack

Answer 49

push(element)

Question 50

How to remove top element from stack and return removed element

Answer 50

pop()

Question 51

Explain what a queue is

Answer 51

First in first out data structure Front holds position of first element Back stores next available space

Question 52

How to check size of queue

Answer 52

size()

Question 53

How to check if queue is empty

Answer 53

isEmpty()

Question 54

How to return top element of queue

Answer 54

peek()

Question 55

How to add to queue

Answer 55

enqueue(element)

Question 56

How to remove element at the front of the queue and return it

Answer 56

dequeue()

Question 57

How does bubble sort work?

Answer 57

Makes comparisons and swaps between pairs of adjacent elements

Question 58

How does insertion sort work?

Answer 58

Inserts elements into the correct position

Question 59

What is the pseudocode for a linear search algorithm

Answer 59

Function linearsearch (search,data[]) Position=-1 For i = 0 to data.length-1 If data [i] == search then Position=i Break Endif Endfor Return position End function

Question 60

What is the pseudocode for binary search algorithm

Answer 60

Function binary search (search,data[]) Position= -1 Lower=0 Upper= data.length-1 While lower < = upper Mid=(lower+upper) DIV2 If data [mid]== search then Position=mid Elseif data [mid]< search Lower=mid+1 Else Upper=mid-1 Endif End while Return position End function

Question 61

Write bubble sort algorithm

Answer 61

Procedure BubbleSort (data[]) Swapped=True While swapped == True: Swapped = false: For n=0 to data.length-2: If data [n]>data[n+1]: Temp=data[n+1] Data [ n+1]=data[n] Data[n]=temp Swapped=True End if Endfor End while End procedure

Question 62

What is the insertion sort algorithm

Answer 62

Procedure InsertionSort(data[]) For i = 1 to data.length -1 Current data = data[1] Position=i While (position >0 AND data[position-1]> current data) Data[position]=data[position-1] Position= position-1 End while Data [position ]= current data End for End procedure