Week 4 - Arrays & Filehandling

Question 1

Array

Answer 1

A container that can hold multiple variables at once.

However, these values must all be of the same type (Eg: all strings, all ints)

Question 2

Multidimensional Arrays

Answer 2

Having an array inside of an array.

Question 3

Dynamic Arrays

Answer 3

Arrays with no set size, meaning you can continue to add values to them.

Question 4

What are the pros and cons of dynamic arrays?

Answer 4

+ They are more flexible
+ Values can be decided in the index position or be put on the end

• The performance isn’t as good as hard coded because the computer has to calculate the memory needed constantly.

Question 5

Rubbish Data

Answer 5

Values that we haven’t assigned but take up storage.

Often the case in Ruby, but will often crash programs in C.

Answer 6

Means to ‘append’.

This means to put the value onto the end of the array.

Question 7

What number do arrays begin indexing from?

Answer 7

0

Question 8

How do we find the number of items in an array?

Answer 8

Using .length

Question 9

What is the best practice sequence with file handling?

Answer 9

Open the file, read/write the file, close the file then continue on with other tasks.

Question 10

What are the cycle methods used in Gosu?

Answer 10

draw(), update() and button_down(id)

Question 11

What’s an alternative to button_down() in Gosu?

Answer 11

Using the update() cycle

Question 12

What does my_array[i] = gets mean?

Answer 12

• It means to assign the value of i to the value in the loop.
• When i=0, it will choose the first element in the array.
• When i=1, it will choose the second element in the array
• More notes on “fill an array” part of the lecture notes

Question 13

How do you open a file to read/write

Answer 13

a_file = File.new(file_name, “r”)

a_file = File.new(file_name, “w”)