F452 - Development.

Writing bad code is easy; writing good code is difficult; writing really good code is REALLY difficult.

What’s a bug?

A bug is where the software (or system) does something unexpected or undesirable.

Not all bugs are accidents though.

Types of bugs:

• Functional: (car will not start)
• Non functional: (the car travels extremely slowly)
• Reproducible:
• Non-reproducible:

[All software has bugs.]

How to write good code:

• Easy to read (Notation).
• Robust/ functional.
• Proceeded by planning.
• Comments.
• Well formatted, readable code.
• Error handling.
• Documentation.
• “Brain sized” chunks.
• Well tested code.
• Understandable by others.

What do you need to design software?

• Brain.
• Pen and paper.

{NO computers, mood room or IDE.}

You CAN (not) do everything.

• Use teams of people to split up work.
• Use software tools to make the interaction easier.

Humans suck at doing stuff; computers suck at designing.

Tools for software development:

• API’s 

[Application Programming Interface](Library of code for use).

• Source control 

(controls additions to the source code, updates everyone's)(versioning; checking in-&-out; branching).

• Build tools 

[compiler] (brings the code together for execution; turns a high level language into machine code)

• Artifact control 

(keeps a compiled copy).

• Documentation.
• Bug tracking software.

(Prioritises issues and assigns tasks to correct the code; links with versioning)

• Automated testing.

• Continuous integration servers/ automated build tools 

(keeps track of everyone's addition and brings it together)

• Automated deployment 

(,e.g: ios distribution).

Software development lifecycles:

Waterfall (traditional):

• Requirements.
• Design.
• Code.
• Test.
• Deploy.
• Support.
• End of life.

Agile (the upstart):

Rough requirement.

Build something that works.

(but that is fully functional).

Refine the requirements.

Build something that works a bit better.

The computer does the testing.

“If the test fails give me a ring; if the test works don’t bother me.”

!xiety (Bangxiety) meter:

• Designed to tell the user when the battery is going to run out.
• Every system has inputs and outputs, even this piece of tech.

Some of the design challenges:

• Reading the wheel speed.
• Recording how much power the batter has used.
• Key presses.