Throwing exceptions in PHP - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an exception in PHP?

An exception is an object that represents an error or unexpected behavior during program execution. It can be "thrown" to signal a problem and "caught" to handle it gracefully.

beginner

How do you throw an exception in PHP?

Use the throw keyword followed by a new Exception object, like this: throw new Exception('Error message');

beginner

What is the purpose of a try-catch block?

A try block contains code that might throw an exception. The catch block handles the exception if one is thrown, preventing the program from crashing.

intermediate

What happens if an exception is thrown but not caught?

If an exception is thrown and not caught, PHP stops the program and shows a fatal error message. This is like the program saying, "I don't know how to handle this problem."

intermediate

Can you throw custom exceptions in PHP?

Yes! You can create your own exception classes by extending the built-in Exception class. This helps you handle specific error types more clearly.

Which keyword is used to throw an exception in PHP?

A error

B catch

C try

D throw

The throw keyword is used to throw an exception.

What does a catch block do?

A Handles an exception

B Throws an exception

C Starts the program

D Ends the program

A catch block handles exceptions thrown inside the try block.

What happens if an exception is not caught?

A Program continues normally

B PHP shows a warning but continues

C PHP stops with a fatal error

D Exception is ignored

If an exception is not caught, PHP stops execution and shows a fatal error.

How do you create a custom exception class?

A By writing a try block

B By extending the Exception class

C By using the throw keyword

D By calling the catch block

Custom exceptions are created by extending the built-in Exception class.

Which of these is the correct way to throw an exception with message 'Error'?

A throw new Exception('Error');

B throw Exception('Error');

C catch new Exception('Error');

D try new Exception('Error');

The correct syntax is throw new Exception('Error');

Explain how throwing and catching exceptions works in PHP.

Think about how you signal a problem and then handle it.

Describe why you might want to create a custom exception class.

Consider how different problems might need different responses.