Logic & Conditionals

Question 1

dog = “satisfied”

if dog == "hungry"
  puts "Refilling food bowl."
else
  puts "Reading newspaper."
end

What will happen?

Answer 1

puts “Reading newspaper.”

Question 2

dog = “thirsty”

if dog == "hungry"
  puts "Refilling food bowl."
elsif dog == "thirsty"
  puts "Refilling water bowl."
else
  puts "Reading newspaper."
end

What will happen?

Answer 2

puts “Refilling water bowl.”

Question 3

dog = “cuddly”

if dog == "hungry"
  puts "Refilling food bowl."
elsif dog == "thirsty"
  puts "Refilling water bowl."
elsif dog == "playful"
  puts "Playing tug-of-war."
elsif dog == "cuddly"
  puts "Snuggling."
else
  puts "Reading newspaper."
end

What will happen?

Answer 3

puts “Snuggling.”

Question 4

How do we write the following as a ternary operator?

age = 1
if age < 2
  "baby"
else
  "not a baby"
end

Answer 4

age = 1

age < 2 ? “baby” : “not a baby”

Question 5

What is the basic structure of a ternary operator?

Answer 5

conditional ? action_if_true : action_if_false

Question 6

What would an if statement modifier look like?

Answer 6

this_year = 2020

puts “Hey, it’s 2016!” if this_year == 2016

Question 7

What would an unless statement modifier look like?

Answer 7

this_year = 2020

puts “Hey, it’s not 2016!” unless this_year == 2016

Question 8

True or False: The following if statement would be a good candidate for using a ternary operator instead.

if condition_a
  something
else
  something_else
end

Answer 8

True

Question 9

How do we turn the following if statement into a ternary operator?

if condition_a
  something
else
  something_else
end

Answer 9

condition_a ? something : something_else

Question 10

What will happen in the following code?

name = “Steven”
puts “Hi, #{name}” if name == “Steven”

Answer 10

puts “Hi, Steven”

Question 11

What will happen in the following code?

name = “Steven”
puts “Hi, #{name}” unless name == “Steven”

Answer 11

Nothing

Question 12

When is it good to use a case statement instead of an if statement?

Answer 12

It’s good to use a case statement when you have a lot of if and elsif statements to check the value of one variable.

Question 13

How would the following if/elsif statement look like as a case statement?

name = “Alice”

if name == "Alice"
  puts "Hello, Alice!"
elsif name == "The White Rabbit"
  puts "Don't be late, White Rabbit"
elsif name == "The Mad Hatter"
  puts "Welcome to the tea party, Mad Hatter"
elsif name == "The Queen of Hearts"
  puts "Please don't chop off my head!"
else
  puts "Whoooo are you?"
end

Answer 13

case name

  when "Alice"
    puts "Hello, Alice!"
  when "The White Rabbit"
    puts "Don't be late, White Rabbit"
  when "The Mad Hatter"
    puts "Welcome to the tea party, Mad Hatter"
  when "The Queen of Hearts"
    puts "Please don't chop off my head!"
  else 
    puts "Whoooo are you?"
end

Question 14

What will happen in the following code?

greeting = “friendly_greeting”

case greeting
  when "unfriendly_greeting"
    puts "What do you want!?"
  when "friendly_greeting"
    puts "Hi! How are you?"
end

Answer 14

puts “Hi! How are you?”

Question 15

What will happen in the following code?

current_weather = “raining”

case current_weather
  when "sunny"
    puts "grab some sunscreen!"
  when "raining"
    puts "grab an umbrella"
  when "snowing"
    puts "bundle up"
end

Answer 15

puts “grab an umbrella”

Question 16

What will happen in the following code?

grade = “A”

case grade
  when "A"
    puts "Good job, Homestar!"
  when "B"
    puts "You can totally do better!"
  when "C"
    puts "Find a mentor to help you!"
  else
    puts "You're just making that up!"
end

Answer 16

puts “Good job, Homestar!”

Question 17

How can we make the following code shorter using the || operator?

if letter == "a"
  true
elsif letter == "e"
  true
elsif letter == "i"
  true
elsif letter == "o"
  true
elsif letter == "u"
  true
else
  false
end

Answer 17

if letter == "a" || letter == "e" || letter ==  "i" || letter == "o" || letter == "u"
  true
else
  false
end

Question 18

What will the following method call return?

def vowels_with_if_single_line(letter)
  true if letter == "a" || letter == "e" || letter == "i" || letter == "o" || letter == "u"
end

vowels_with_if_single_line(“r”)

Answer 18

False