Project start with analysis and design

So how do we identify the needs of our system

Where do you start?

• project brief, if you are given a project breif or write one your self the project breif should state the problem you would like to solve and any related ideas and constraints you have on the project. This is done in plain english

Finding the needs!

Is a process of finding the subjects and verbs of the project brief and formalise them as testable statements, once that is done we do our firast iteration of risk analysis on those sets.

Needs determination

We now look at the Course project and start setting upp our first development diagrams and design documents for the course project.

Hint!

Start by looking at the example design document How we design

Hint!

Analyse the project breif and make 5 short statements about the software

Requirements matrix to Feature list

Using the Requirements and risk matrix we can design a feature list these can be tracked using issues in Git or in a separate document the feature list describes how to solve a requirment in plain text english and with flowcharts

Design

The design process takes over once you have completed the anlaysis phase (Needs/requirements gathering, risk assesment of needs and the software process) Once we have identified the features and needs engough to start our software it is time to start designing our system. Depending on the aproach or paradigm we follow we will endup with diffrent design documents the idea of the process is to give us a record of our thoughs and to be able to explain our design choices to others. In general flowcharts and sequence diagrams are used to describe events or information flow and in an object oriented paradigm the use of class diagrams build our class structure which is the Data and enacapsulated behaviour we have modeld.

The reason to chose an objectoriented aproach in this case is because of the smaller semantic gap from reality to model and that it is a very common model. When we keep developing you will see that we will use many diffrent paradigms that work together, a project is not nescessary one or the other, One of the design principles of functional programming I like to adhere to even if I design object oriented is from functional programing it can be summariezed in that a fuction or method should only have one output and no side effects. That is the effect should only affect the parameter that you e.g. SetSpeed() only sets the speed of the bacteria and does not affect rotation, the method move is a composition of changedirection and setspeed and changeposistion

classDiagram
    Move *-- set_speed
    Move *-- set_direction
    Move *-- change_position

Object design

In object design we try and find the objects that will help us identify the classes of our project and here is a link to a tutorial for python

What are the main concepts of object design

Model the realworld through classes Facilitate information hiding through Encapsulation Facilitate reusability through inherentance Interaction through behaviour

Exercise Model the Features of the projects as objects

using the graph feature of mermaid graph TD model objects that will be translated into the classes we will implement

Hint!

This is a basic representation of what an object diagram for bacterial simulation could look like

graph TD;
A(Simulation) -->|initialize| B(world);
C(bacteria) -->|exits in| B;
C -->|moves twoards| D(Food Source);
C--> |consumes| D
A-->|updates|A
E(Graphical User Interface)-->|Displays|A

classDef red fill:#f9cccc,stroke:#333,stroke-width:2px;
classDef orange fill:#ffe6cc,stroke:#333,stroke-width:2px;
classDef green fill:#ccffcc,stroke:#333,stroke-width:2px;
classDef blue fill:#00aaff,stroke:#333,stroke-width:2px;

class A red;
class B, orange;
class C,D,G green;
class E blue

Class diagrams

A good way to show your design is through class diagrams which shows the relationships and the class definitions A class is and abstraction of an object where its Data is abstracted as attributes and its behaviour as methods

Exercise

Taking our feature list of requirments and object modeling now we try and find the classes and model a class diagram that implements those features.