C++ Exception Handling Interview Questions and Answers for 5 years experience

1. What is exception handling in C++?

   • Answer: Exception handling is a mechanism in C++ that allows you to gracefully handle runtime errors or exceptional situations that might occur during program execution. It separates error-handling code from the main program logic, improving readability and maintainability. It uses `try`, `catch`, and `throw` keywords.

2. Explain the `try`, `catch`, and `throw` keywords.

   • Answer: `try` block encloses the code that might throw an exception. `throw` keyword is used to explicitly throw an exception. `catch` block handles the exception thrown by the `try` block. Multiple `catch` blocks can handle different exception types.

3. What are the different types of exceptions in C++?

   • Answer: C++ supports both built-in exceptions (like `std::exception`, `std::runtime_error`, `std::logic_error`, etc.) and user-defined exceptions (classes derived from `std::exception`). Built-in exceptions represent common runtime errors, while user-defined exceptions allow you to create custom exception types tailored to your application's specific needs.

4. What is the difference between `std::exception` and `std::runtime_error`?

   • Answer: `std::exception` is the base class for all standard exceptions. `std::runtime_error` is a derived class representing errors that occur during program execution, such as invalid arguments or resource exhaustion. `std::logic_error` represents errors detectable before runtime, such as using a function with invalid input parameters.

5. How do you handle multiple exceptions in a single `try` block?

   • Answer: You can use multiple `catch` blocks after a `try` block. The compiler will match the thrown exception to the `catch` block that handles its type (or a base class). The order of `catch` blocks matters; more specific exception types should come before more general ones.

6. What is the purpose of the `catch(...)` block?

   • Answer: The `catch(...)` block is a catch-all handler. It catches any exception that is not handled by previous `catch` blocks. It should be used cautiously and usually only as a last resort to prevent unexpected program termination.

7. Explain exception specifications (deprecated).

   • Answer: Exception specifications, using `throw()`, were used to declare which exceptions a function could throw. However, they are considered deprecated in modern C++ because they can lead to unexpected behavior and are difficult to use effectively. Modern C++ emphasizes RAII (Resource Acquisition Is Initialization) and exception safety techniques over restrictive exception specifications.

8. What is stack unwinding?

   • Answer: When an exception is thrown, stack unwinding is the process of the runtime environment automatically calling destructors for objects on the stack between the point where the exception was thrown and where it's caught. This ensures proper resource cleanup (e.g., closing files, releasing memory) even if an error occurs.

9. How can you create a user-defined exception class?

   • Answer: Create a class that inherits from `std::exception` (or another suitable exception class). Provide a constructor to initialize relevant error information, and optionally override the `what()` method to provide a descriptive error message.

Thank you for reading our blog post on 'C++ Exception Handling Interview Questions and Answers for 5 years experience'.We hope you found it informative and useful.Stay tuned for more insightful content!