Variables

Question 1

What is a variable?

Answer 1

A way to store information to be referenced and manipulated in a computer program

Question 2

What do variables do?

Answer 2

Provide a way of labelling data with a descriptive name

Question 3

What is the sole purpose of a variable?

Answer 3

To label and store data in memory

Question 4

When naming a variable, what is considered good practice?

Answer 4

Making sure the name assigned to the variable is accurately descriptive and understandable to the reader

Question 5

How would we get rid of the newline at the end of a string?

Answer 5

Add .chomp to the end of that string

Question 6

What does a newline character represent?

Answer 6

Hitting the enter key

Question 7

What does a variable’s scope determine?

Answer 7

Where in a program a variable is available for use

Question 8

How is a variable’s scope defined?

Answer 8

A variable’s scope is defined by where the variable is initialized or created

Question 9

How is a variable’s scope defined in Ruby?

Answer 9

By a method definition or a block

Question 10

What is a method?

Answer 10

A piece of reusable code that your program can execute many times during its run

Question 11

What does ‘methods have self contained scope’ mean?

Answer 11

Means only variables initialized within the method’s body can be referenced or modified within the method’s body

Question 12

Are variables initialized within a method’s body available outside of it?

Answer 12

No

Question 13

What is a block?

Answer 13

A piece of code that follows a method’s invocation, delimited by either curly braces or do/end

Question 14

What is one rule we need to emphasize with blocks?

Answer 14

Inner scope can access variables initialized in an outer space, but not vice versa

Question 15

How do we know if curly braces or do/end delimiting code is a block?

Answer 15

By seeing if they immediately follow a method invocation. If they do, it is a block

Question 16

What are the 5 types of variables?

Answer 16

1. Constants
2. Global variables
3. Class variables
4. Instance variables
5. Local variables

Question 17

How are constants declared?

Answer 17

By capitalizing every letter in the variable’s name

Question 18

What are constants used for?

Answer 18

For storing data that never needs to change

Question 19

Can you change the value of a constant?

Answer 19

In most coding languages - no. In Ruby, yes.

Question 20

Can constants be declared in method definitions?

Answer 20

No. They are available throughout your application’s scopes

Question 21

How are global variables declared?

Answer 21

By starting the variable name with a $ (dollar sign)

Question 22

Where are global variables available?

Answer 22

Throughout your entire app, overriding all scope boundaries

Question 23

How do you declare a class variable?

Answer 23

By starting the variable name with @@

Question 24

Where are class variables accessible?

Answer 24

They are available by instances of your class, as well as the class itself

Question 25

When would you use a class variable?

Answer 25

When you need to declare a variable that is related to a class, but each instance of that class doesn’t need its own value for this variable

Question 26

Where do you initialize a class variable?

Answer 26

Must be initialized at the class level, outside of any method definitions

Question 27

How can you alter a class variable?

Answer 27

Using class or instance definitions

Question 28

How do you declare a instance variable?

Answer 28

By starting the variable name with @

Question 29

Can instance variables cross scope boundaries?

Answer 29

Some, but not all of them

Question 30

How do you declare a local variable?

Answer 30

Variable = data

Question 31

Which boundaries do local variables obey?

Answer 31

They obey all scope boundaries