Software 34

Benefits of using prompts to generate code

quick code generation

increased productivity for the rest of the team

enables non-developers to create code

automated documentation

Disadvantages of using prompts to generate code

potential for bugs and errors

risk of vulnerabilities

copyright concerns

limited situation understanding

Benefits of automated debugging and testing

real time identification of issue

improved code quality

Disadvantages of automated debugging and testing

reduced opportunities for developers and testers

dependency on training data

Functional Requirements

what the system should do and how it should behave in response to different inputs and conditions

Non-functional requirements

Non-functional requirements are attributes or qualities of a system that specify how it should behave or perform, rather than what it should do. Including: usability, reliability, portability, robustness and maintainability.

Data dictionaries

Used to design the data of a solution and useful at later stage when code needs to be modified later by other programmers and the purpose of the variable is unknown.

Mockups

A detailed diagram that illustrates how software modules’ interface will look. Annotations used to explain how design principles and characteristics of UX have been incorporated.

Object descriptions

Used to design an object within a solution. Includes the name, list of attributes/properties and the methods. Establish the naming conventions for the system, and document OOP principles.

Input process output charts

Provide brief overview of the inputs and outputs of a task and outline the processes required to generate outputs.

Pseudocode

Structured english which clearly depicts algorithms in a way that does not require technical knowledge. Helps break down complex problems. Helps identify logical erros early in development.

Character

Represents a single text symbol, contains one byte of memory

String

Represents a sequence of characters. Use string if the number has a leading 0 such as phone numbers or any other number that is dependent on the specific structure of the number.

Integer

Represents whole numbers, positive, negative and zero values. measurements such as mm

Floating point

Represents numbers with decimals, used for measurements such as cm and metres

Date/time

represents date and time information, enables mathematical operations with dates

Boolean

Use to store default true or false data

Data structure

Method of organising data to allow particular operations to be performed on them efficiently

One dimensional array

Linear data structure where elements are accessed by a single index. It represents a list of elements that are all of the same data type. Each element in the array can be accessed using an integer index.

Two dimensional array

Two dimensional array represents a grid of data, rows and columns. This requires accessing elements using two indices rather than one.

Records

Basic data structure for collections of related elements. These elements may or may not be of the same data type.

Fields

Are what make up records and have their own data type.

XML

File structure made up of user defined, self descriptive tags that are customizable. Ensures that data received from a source is in an ‘as expected’ format. XML will continue to work if data is modified or added.

CSV

Text file where data is seperate by comma, can store two dimensional arrays, much simpler design.

XML vs CSV

XML is easier to move data bewteen systems as it conforms to standard structure

XML is more human readable

XML can store hierachial complex data

changing csv by adding more columns may require code altercations where changing XML doesn’t

Managing XML requires more complex code than CSV

OOP

Code that is reusable and modular that revolves around objects which are from classes that hold data or code and organized in methods.

Abstraction

Hiding the complex implementation details of a class and only exposing the necessary and relevant parts to the user

Encapsulation

Process of restricting direct access to an objects components by modifying only through exposed methods. Improves the security and integrity of the data.

Inheritance

When a subclass inherits common attributes and methods from an existing super class. Allows the subclass to reuse code, extend its functionality and promote hierarchial structure. Any changes made to the methods in the super class will be affected in the subclass.

Generalisation

The process of finding common characteristics among a set of classes and abstracting them into a parent class.

Benefits of inheritance and generalisation

Code reusability, Ease of maintenance and Scalability

Public modifier

Scope is global as they are accessible from any part in the program. Their lifetime extends throughout the entire runtime of the program.

Protected modifier

Accessible only within the class they are defined in and by any subclasses inherited from that class.

Private modifier

Accessible from within the exact class which they were declared and lifetime limited to the the extent in which the method or specific class in running for.

Local variable

Are declared inside a function and can only be accessed within that specifc function. Their lifetime is limited to whne they are created when the function is called and destroyed when the function completed it execution.

Global Variable

Are declared outside any function and can be accessed throughout the entire program.

Sequence

A set of instructions that executes line by line, each line is run in the order is is written.

Selection

Lines of code are run only when a condition is met, based on a Boolean condition. (IF statements)

Iteration

Is used to repeat sections of code multiple times until a condition is met. (WHILE, DO/WHILE, FOR and REPEAT/UNTIL)

Function

A reusable block of code designed to perform a specific task

Method

A function that called from the object in which it was declared

Class

A template for objects with predetermined variables and behavior, which can be instantiated as objects or be used by another class.

Objects

An instance of a class that represents a specific entity with its own unique state

Naming conventions

Is a set of rules that is used when creating variables, making them easy to read and understand. Should tell the purpose and data type or structure.

Hungarian notation

same as camel case but has data type as prefix

Snake case

Joins words using an underscore

Camel case

when each word after the first begins with a capital letter

Internal documentation

Helps other developers to understand what the code does such as data structures, helps reduce the amount of time required for maintaining and debugging. Useful for future software updates. Improves efficiency

Selection sort

Comparing the first element of the list to each other element to find the smallest value and moving it to the front

Quick sort

Method of sorting an array by splitting and swapping values in that array.

Quick sort vs selection sort

Quick sort is much more efficient than selection sort as it uses the divide and conquer method. Exponentially faster. Where as selection sort checks every value in the list and compares it to the smallest which is much less efficient.

Linear search

Method of searching an UNSORTED list, going through each element first to last. Simple to implement, but extremely inefficient is a large data set is used.

BInary search

Method of searching a SORTED list, by dividing the data set in half until the value is found. Harder to implement as requires sorted array but is much more efficient than linear. List must be sorted in order of the element trying to search for.

Syntax error

erros in code that prevent a solution from being compiled as a result of a programming language’s syntax not being followed

Logic errors

errors in code that result in the solution generating incorrect output

Run-time erros

errors that arise during program execution that result in the solution crashing if not handled correctly

Over flow error

When a calculation produces a result that exceeds the storage capacity of the data type used to store it.

Index out of range

When a program attempts to access an element at an index that is outside the bounds of an array or collection.

Type mismatch

When values of incompatible data types are combined in an operation.

Techniques for debugging

Breakpoints, debugging statements

Breakpoints

Markers set by a developer in a code editor or debugger that pauses the execution. Allows developers identify and fix issues in their code

Debugging statements

Lines of code that offer insight into how the data is being manipulated. Can be inefficient as the whole program has to be run. Commenting out code

Testing techniques

Boundary condition tests

Reasons for developing software

Increasing productivity and efficiency, reducing costs, identifying opportunities in the market and meeting organizational objectives.

Features of design brief

problem outline, proposed users, language to use, feasibility, originality

Milestones

Represent the achievement of a significant stage such as the development stage, analysis stage etc.

Dependencies

The commencement of some tasks depends directly on the tasks that is completed before

Critical path

Sequence of tasks which contains no slack time, the minimum possible amount of time which all

Monitoring the progress of projects

Annotate the Gantt to log any unforeseen changes or using a project change log

Interviews

A method of collecting in depth qualitative data, can ask follow up questions. Quite costly in labour and time and can only interview small number of people

Survey

Mix of quantitative and qualitative questions, can be statistically analysed, can reach out to many participants being geographically diverse

Observations

Observing user behaving normally in natural environment, useful to collect data bout current system. Potential for observer bias, but does not rely on users’ opinion.

Reports

summarises information about a system, used to analyse an existing system

Economic constraint

financial limitations and time considerations that may affect the ability of a project to be developed

Legal Constraint

Laws and regulations that must be adhered to in the development of the project

Social constraint

Refer to the constraints of the system to accommodate for users with varying technical knowledge and accessibility needs

Technical constraints

The restrictions related to the technology used in the project

Scope

Outlines what the solution will and will not address, some requirements may not be addressed due to identified requirements

Scope creep

When a client increases the scope of a project during the life cycle of the project. This can be very expensive for the developer in terms of time and money.

Context diagram

Used to represent the data flows between a system and external entities are Level 0.
Data cannot flow directly between two entities

Data flows cannot cross each other

Each data flow should only represent a single set of information being transferred.

Data flow diagram

Depict the flow of data within a system, illustrating how data is provided, processed, stored and output. Level 1.

Data cannot flow directly between entities

Data cannot flow directly between data stores

data cannot flow directly between an entity and data stores.

data flows cannot cross each other

a process must have at least one input and one output

output name from process should be different to the name for the input

data store must have at least one input and one output.

all external entities must at least provide one input or receive one output from the system

Use case diagram

Visually represents the interactions between users and a system

SRS

a document that summarises the findings of the analysis stage

User characteristics

Technical proficiency, cognitive abilities and demographic information

Components of SRS

requirements, constraints, scope, user characteristics, technical environments and analytical tools.

Version control

Ensures the files that developers are working on are up to date and allows them to ‘roll back’ to any previous point in the development if issue develops with current version

Backup scheme

frequency of backup, backup media, location of backup, testing, backup media, backup type, restoration, retention period, amount of data

Archive vs backup

Archiving is moving files from one place to another whereas backup copies files from one place to another

Full backup

copy everything to new storage is time consuming and needs large amount of storage.

Differential backup

Full backup first and any changed files different to this are saved in the next backup. More complicated to implement and restore backups

Incremental

full backup first and any changed files different to previous increment, very quick, complicated to restore as full back up and then all increments in order

File security

Access control, file permissions and encryption

Disposal

The removal of files tat are no longer needed, ensures that storage space is optimised and sensitive information is protected

Mood boards

used to collate imagery, colours, typography and code samples to explore and inspire the overall direction of the design of the software solution.

Brainstorming

The unstructured collation of related ideas, based around a central theme/concept

Mind maps

a structured collation of related ideas, based around a central theme/concept

sketches

unrefined illustrations that briefly depict an interface or indicate how different components of the software solution could be linked or interact

Annotations

can be used to organise thoughts and highlight or justify design considerations within design ideas. Justify design principles and characteristics of user experience.

Efficiency of solution

how well the solution utilises resources and performs tasks minimising cost and time and speed of processing

Effectiveness of solution

The ability to achieve its intended goals, accessibility, accuracy, attractiveness, clarity, communication of message, completeness, maintainability, readability, relevance, timeliness and usability