Week 4

Question 1

programming language used and its issues

Answer 1

C++, arduino does not understand so has to compile, this can cause syntax errors (does not compile) or runtime errors(compiled but did not run correcttly), which will only manifest itself when it is being ran

Question 2

char and strings

Answer 2

single charcter of text, or a number between 0 and 255, strings ar a char type array

Question 3

functions

Answer 3

a block of code that performs a single task.
functions define a return type ( a variable that is returned by the function), if ther eis no returned variable, the return type is void
functions can define required attributes
it can only be useed after it is defined

Question 4

setup

Answer 4

• Reading the setup should tell you:
• The initial state of the program
• What systems are used by default
• What needs to be done before the system is ready
• Use functions for complex tasks (readability!)
• Use line breaks to divide code in clear units
• Use comments if it helps understanding the code

Question 5

loop

Answer 5

• Loop just calls a bunch of functions
• Functions should be non-blocking
• Reading the loop should tell you:
• What the program does during normal operation.
• What tasks run in parallel
• What influences operation
• What function is available when

Question 6

declarations

Answer 6

“The stuff at the top of your code files”
* Start with includes and defines
* Then variables
* Then class instantiations
* Then function declarations
* When reading a declaration you learn:
* What does a program require
* What are the settings
* How are things connected

Question 7

three main conventions for beautiful code

Answer 7

• Documentation
• Casing
• Blocks / indentation

Question 8

Documentation

Answer 8

Start your program file with a clear
comment.
* Add program name
* Describe its purpose
* Note down who wrote the program
* And: when it was written
* You can also add license and copyright
information here. Do you allow others
to use it, and if so under what
conditions?
* You can add links for more information
* Make sure to also document all
functions and variables

Question 9

three types of casing and when to use

Answer 9

*lowerCamelCase is commonly used for:
* Variable names
* Class method names
* Function names
UpperCamelCase is commonly used for:
* Class names
* “global” functions
UPPER(SNAKE)CASE is commonly used for:
* Static constant variables (variables that do not change during the run of the program)
* Macro’s (#define

Question 10

when do you have badly organised code

Answer 10

when indenting is deeper then 4 levels

Question 11

keywords in loops

Answer 11

• The “break” keyword can be used to break out of a loop prematurely
• The “continue” keyword breaks the current iteration of the loop.

Question 12

how to use blocking vs non-blocking cells in a your code

Answer 12

• General rule: use blocking code only in your setup().
• General rule: only use non-blocking calls in your loop()

Question 13

when are delays suitable

Answer 13

only for initiation and throttling

Question 14

timing using system time

Answer 14

For non-blocking timing System time can be used
* Arduino counts the process ticks since it was last powered up
* And calculates milliseconds or even microseconds since boot.
* These values are available through millis() and microSeconds()

Question 15

use switch statement

Answer 15

if there are many alternative statements for a conditional. use

switch(state)
case 1
case 2

Question 16

short hand

Answer 16

a<b ? y:z
only used when initiating a based condition

Question 17

Statemachines

Answer 17

• A state machine is a model of computation
• It consists of states and transitions between states
• It can only be in one state at a time
• Very powerful, because self-explanatory
• Code represents structure 1:1
• Easy to debug
• If you can draw your system as a flow chart, you can make it into a state machine
• States define what your system does at a particular moment
• Transitions define conditions for changing from one state to another

Question 18

How to declare statemachine

Answer 18

first declare the states and transistions, then add the states to the machiiene
then add transisions
and then tell loop to run the machine

Question 19

libraries (code seperation)

Answer 19

a library is essentially seperated code. allows to cut difficult tasks into easy chuncks, increases readability

Question 20

class

Answer 20

a class is the blueprint for creating objects, they can contain data and functions. they are self contained

Question 21

object

Answer 21

• An Object is an initiation of a Class
• The lifecycle of an Object starts with the
  execution of the (or one of the) constructor(s)
• The lifecycle ends with a call to the
  (optional) destructor (~)
• The constructor is like the Setup of the
  main sketch it prepares memory and variables.
• The destructor is where you can free memory

Question 22

create your own libraries

Answer 22

reuse code in multiple projects, easy to acces to work and is maintainable