Custom exception classes in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a custom exception class named MyError.

Ruby

class MyError < [1]
end

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AException

BStandardError

CRuntimeError

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Inheriting directly from Exception can cause unexpected behavior.

Using a non-existent class like Error will cause a NameError.

Custom exceptions in Ruby usually inherit from StandardError to behave like typical errors.

2fill in blank

medium

Complete the code to raise the custom exception MyError with a message.

Ruby

raise [1], "Something went wrong"

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AMyError

BMyError.new

CStandardError

DException

Attempts:

3 left

💡 Hint

Common Mistakes

Using MyError.new raises an instance but is not the common pattern.

Raising Exception or StandardError raises built-in errors, not the custom one.

To raise a custom exception with a message, use raise MyError, "message".

3fill in blank

hard

Fix the error in the code to rescue the custom exception MyError.

Ruby

begin
  # some code
rescue [1] => e
  puts e.message
end

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ARuntimeError

BStandardError

CException

DMyError

Attempts:

3 left

💡 Hint

Common Mistakes

Rescuing Exception or StandardError catches too many errors.

Using RuntimeError does not catch MyError unless it inherits from it.

To catch a custom exception, rescue it by its class name MyError.

4fill in blank

hard

Fill both blanks to define a custom exception with a message method.

Ruby

class MyError < [1]
  def [2]
    "Custom error occurred"
  end
end

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AStandardError

Bmessage

CException

Dinitialize

Attempts:

3 left

💡 Hint

Common Mistakes

Defining initialize instead of message changes how the error is created.

Inheriting from Exception is less common and can cause issues.

The custom exception inherits from StandardError and defines a message method to return the error message.

5fill in blank

hard

Fill all three blanks to raise and rescue a custom exception with a message.

Ruby

begin
  raise [1], "Oops!"
rescue [2] => e
  puts e.[3]
end

Drag options to blanks, or click blank then click option'

AMyError

Cmessage

DStandardError

Attempts:

3 left

💡 Hint

Common Mistakes

Raising and rescuing different exception classes causes errors.

Using e.to_s instead of e.message changes output format.

This code raises MyError with a message, rescues it, and prints the message using e.message.