V8

Question 1

what are algorithms

Answer 1

• a list of a discrete number of steps that, when followed, will complete a certain task (or fail)

Question 2

state diagrams

Answer 2

used to describe the behaviour pf a system
- visualisation of an algorithm
very similar to a flow chart
- state diagrams respond to actions/events
- flowcharts do not need explicit events

Question 3

for/for each loop

Answer 3

• modelled very close to natural language

- > for(x in 1:ncol(M)) = for each x going from 1 to the umber of columns in M

Question 4

while loop

Answer 4

• less natural bur more flexible

Question 5

design pattern

Answer 5

• general reusable solution to a commonly occurring problem within a given context in software design
• not a finished design that can be transformed directly into source or machine code, is a template for how to solve a problem that can be used in many different situations
• to avoid reinventing the wheel

Question 6

design patterns: some examples

Answer 6

• model view controller(MVC): used in web development
• monte carlo sampling: everything that might happen , used in genetics, economics, agriculture, etc.
• facade pattern - provide a stable call - interface
• scheduler - ways to schedule tasks in a certain time

Question 7

recursion + example sum up 7 (calculates 1+2+3+4+5+6+7)

Answer 7

• a function calling itself
• a simple base case (or cases)
• rules that reduce all other cases toward the base case

example:

sumUp

Question 8

important notes for recursion

Answer 8

• hand weird/unexpected input
• there is a recursion limit in R
• > set limit by : options(expressions = 500)
• every time we call our function : a new function call is created, internal variables need to be stored

Question 9

• recursion invariant

Answer 9

sumUp if input negative then the ‘ summing up’ becomes infinite
- there is no stop for negative numbers

Question 10

why use recursion

Answer 10

• in many programming languages - more efficient, cleaner code, often more in line to how people think about problems

Question 11

indirect recursions

Answer 11

then can return different functions within each other

-> that makes them indirect - what the purpose of this is, i have no idea