Higher Computing Science (Software and Development)

Higher Scottish computing science SQA software and development flashcards.

Iterative Development Methodology

• Client only involved at start of project and one at the end

• Heavy documentation at each stage

• Strict Deadlines

• Low adaptability

• Testing carried out at end of implementation stage

Agile Development Methodology

• Regular meetings with clients and developers

• Minimal amount of documentation

• Short term goals (sprints) to measure progress

• Flexible when needing to change

• Testing carried out when programming being done

Functional Requirements

Inputs, Processes and Outputs performed by features and functions of the software

Scope

List of items that project will deliver to the client

Boundaries

Limits that define what is in the project and what is not in the project e.g. Validation for inputs

Wireframe

A skeletal outline of the components of the interface is sketched

Structure Diagrams

Illustrates how a program is divided up into smaller parts in a series of steps of refinements

Data Flow

List the subprograms and to detail which paraments require to be passed in and out of each subprogram

Records

class Country:
	name : str
	capital : str
	population : int

Local Variables

• Only exists within subprogram where it is declared

• Only changed in that subprogram and not anywhere else

Global Variable

• Variable recognised within all subprograms within subprogram

• Can be changed by any subprogram

• Aim is to minimise amount of global variables as it has to be traced in all others - lower efficiency

Procedure

Subprogram where it produces and effect e.g. printing something to a screen

Function

Subprogram which returns a single value e.g. a calculation

Formal Parameter

Variable or value that is passed when function is declared

Actual Parameter

Variable or value that is passed when function is called

Substrings

a = "Hello World"
print(a[:5]) #<--- Will print output hello

Ord

Turns characters into numerical numbers

Chr

Turns integer into ASCII character

Files

creating file - open(filename, “x”)

reading file - open(filename, “r”)

writing file - open(filename, “w”)

appending file - open(filename, “a”)

Linear search algorithm

Code searches for a value - inputted by the user - inside of a list

Finding maximum algorithm

Find the maximum value in a list

Finding minimum algorithm

Find the minimum value in a list

Counting occurrence algorithm

Counts how often a value entered from user occurs in a list of items

Types of data tested for

• Normal data -Test is software gives correct results for commonplace data

• Test if software can handle data on edge or limit of validation

• Test if software can handle invalid data to test for software robustness

Syntax error

Mistakes in the grammar of the programming language

Execution error

Mistakes only found when program is executed

Logical error

Does not give correct results even with no execution or syntax errors

Dry run

Going through the program instructions and manually updating all of the variables usually in a table

Trace table

The programmer goes line by line and updates each variable if they have been changed after each instruction has been executed

Break Point

When program reaches breakpoint the execution is suspended so variable values can be assessed

Watch Point

Conditional breakpoint that stops execution if a certain condition is met e.g. Variable meeting certain value

Fitness for purpose

If program meets the user and functional requirements it is suitable for its intended purpose

Efficiency

• Arrays make a program more efficient than lots of individual variables

• Nested if statements increases efficiency as rest of code not executed

Usability

Describes how intuitive software is from a users point of view

Maintainability

• Readable code e.g. Meaningful variable names, comments, indentations and white space

• By using subprograms

Robustness

Software does not crash easily with unexpected input then it is robust