Case/when statement in Ruby - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple case/when statement

What is the output of this Ruby code?

Ruby

value = 3
result = case value
         when 1 then "One"
         when 2 then "Two"
         when 3 then "Three"
         else "Other"
         end
puts result

A Two

B Three

C Other

D One

💡 Hint

Check which 'when' matches the value 3.

The case statement compares 'value' to each 'when'. Since value is 3, it matches 'when 3' and returns 'Three'.

❓ Predict Output

intermediate

Case statement with multiple matches

What will this Ruby code print?

Ruby

grade = 'B'
result = case grade
         when 'A', 'B' then "Pass"
         when 'C' then "Average"
         else "Fail"
         end
puts result

A Average

B Error

C Fail

D Pass

💡 Hint

Look at the first matching when clause with multiple values.

The case matches 'B' in the first when clause ('A', 'B'), so it returns 'Pass'.

🔧 Debug

advanced

Identify the error in this case/when statement

What error does this Ruby code raise?

Ruby

value = 5
case value
when 1
  puts "One"
when 5
  puts "Five"
else
  puts "Other"
end

A SyntaxError: unexpected end-of-input, expecting 'end'

B NoMethodError: undefined method 'puts' for nil:NilClass

C No error, prints 'Five'

D RuntimeError: case expression error

💡 Hint

Check if all blocks and the case statement are properly closed.

The case statement is properly closed with 'end', so no syntax error occurs.

❓ Predict Output

advanced

Case statement with range conditions

What is the output of this Ruby code?

Ruby

score = 75
result = case score
         when 0..59 then "Fail"
         when 60..79 then "Pass"
         when 80..100 then "Excellent"
         else "Invalid"
         end
puts result

A Pass

B Excellent

C Fail

D Invalid

💡 Hint

Check which range includes 75.

75 falls in the range 60..79, so the case returns 'Pass'.

🧠 Conceptual

expert

Behavior of case/when with no matching condition

What will be the value of 'result' after running this Ruby code?

Ruby

value = :unknown
result = case value
         when :one then 1
         when :two then 2
         end

A nil

B 0

C Raises an error

D false

💡 Hint

What does case return if no when matches and no else is given?

If no when matches and there is no else, case returns nil.