Throwing exceptions in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does it mean to throw an exception in C++?

Throwing an exception means signaling that an error or unexpected event has occurred, by using the throw keyword followed by an object representing the error.

beginner

How do you throw an exception with a message in C++?

You can throw an exception by writing <code>throw std::runtime_error("Error message");</code> where <code>std::runtime_error</code> is a standard exception class that takes a message.

beginner

What happens after an exception is thrown?

The program stops normal execution and looks for a matching catch block to handle the exception. If none is found, the program usually terminates.

intermediate

Can you throw any type of object as an exception in C++?

Yes, C++ allows throwing any type of object, but it is recommended to throw objects derived from std::exception for consistency and better error information.

beginner

Write a simple C++ code snippet that throws and catches an exception.

<pre>#include &lt;iostream&gt;
#include &lt;stdexcept&gt;

try {
    throw std::runtime_error("Something went wrong");
} catch (const std::exception &amp;e) {
    std::cout << "Caught exception: " << e.what() << std::endl;
}</pre>

Which keyword is used to throw an exception in C++?

A throw

B catch

C try

D except

The throw keyword is used to signal an exception in C++.

What happens if an exception is thrown but not caught?

A Program continues normally

B Exception is ignored

C Exception is automatically handled

D Program terminates

If no matching catch block is found, the program usually terminates.

Which of these is a recommended base class for exceptions in C++?

A std::string

B std::exception

C std::vector

D std::cout

std::exception is the standard base class for exceptions.

How do you catch an exception of type std::runtime_error?

A catch (std::runtime_error &e)

B catch (int e)

C catch (std::string e)

D catch (float e)

You catch exceptions by specifying the type in the catch block.

Which block is used to write code that might throw an exception?

A finally

B throw

C try

D catch

The try block contains code that may throw exceptions.

Explain how throwing and catching exceptions works in C++.

Think about how the program stops normal work and looks for a handler.

Write a simple example of throwing an exception with a message and catching it.

Use std::runtime_error and std::exception for your example.