Raise for throwing errors in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the raise keyword do in Ruby?

The raise keyword stops the program and throws an error. It can also create a custom error message.

beginner

How do you raise a standard error with a custom message in Ruby?

Use raise "Your message here". This stops the program and shows your message as the error.

intermediate

What happens if you use raise without any arguments?

Ruby re-raises the last error that was caught. If no error was caught, it raises a generic RuntimeError.

intermediate

How can you raise a specific error type in Ruby?

Use raise ErrorType, "message". For example, raise ArgumentError, "Invalid argument".

beginner

Why is using raise useful in programming?

It helps catch problems early by stopping the program when something unexpected happens. This makes bugs easier to find and fix.

What does raise "Error happened" do in Ruby?

A Ignores the message and continues

B Prints 'Error happened' but continues running

C Stops the program and shows 'Error happened' as an error message

D Creates a warning but does not stop the program

Using raise stops the program and shows the message as an error.

Which of these raises a specific error type in Ruby?

A error "Wrong input"

B raise ArgumentError, "Wrong input"

C throw ArgumentError

D raise "Wrong input"

The syntax raise ErrorType, "message" raises a specific error type.

What happens if you call raise with no arguments inside a rescue block?

A It re-raises the last caught error

B It raises a new generic error

C It does nothing

D It prints a warning

Calling raise without arguments inside rescue re-raises the last error.

Why should you use raise in your code?

A To print messages to the user

B To speed up the program

C To create variables

D To stop the program when something goes wrong

raise stops the program when an error occurs, helping find bugs.

Which keyword in Ruby is used to throw an error?

A raise

B throw

C error

D catch

The raise keyword is used to throw errors in Ruby.

Explain how to use raise to create a custom error message in Ruby.

Think about how you tell Ruby to stop and show your own message.

Describe the difference between using raise with and without arguments.

Consider what happens when you call raise alone versus with a message.