Multiple Choice Quiz

1. When you create a unique pointer you can provide a function to run on deletion. Why is this useful?

(A) You can use this to ensure that no other pointers are referring to this object before deleting it.

(B) You can have it perform additional actions to manage resources, such as closing files or releasing sockets.

(C) It is an excess feature in the interface that has little practical utility.

(D) You must do this to make sure to delete the associated pointer.

2. Which of the following is _NOT_ an instance of undefined behavior in C++?

(A) Dereferencing a null pointer

(B) Accessing an object after free has been called on it

(C) Having a return statement in a void function

(D) Accessing un-initialized variables

(E) Reading off the end of an std::vector

3. Why should you use std::make_unique instead of new when constructing a unique_ptr?

(A) They are functionally identical and it doesn't matter.

(B) To delay object creation until first usage.

(C) To manually manage memory.

(D) To ensure exception safety and efficiency.

4. What is the advantage of a "time-traveling" debugger?

(A) They allow you to make temporary changes to debug your code that you can then rewind back to their original state.

(B) None. Time-traveling debuggers are purely theoretical and do not exist yet.

(C) They allow you to trace back how variables got the values they currently have without needing to restart a run.

(D) The produce graphs of variable values over time to help you identify unexpected correlations.

(E) They work with git repositories to trace back when in time a bug was introduced to your code.

5. What happens when you run std::move() on a unique_ptr value?

(A) The unique_ptr is converted into a raw pointer, but otherwise unmodified.

(B) The pointed-to object is copied to a different position in memory and that new position is returned.

(C) The pointed-to object is moved to a specified position in memory and the unique_ptr's value is updated to this new position.

(D) The pointed-to memory stays where it is, but is marked as being allowed to be assigned (shifting ownership) to a different pointer.

6. For which of the following is static_cast NOT appropriate?

(A) Converting between numeric data types (e.g., int to float).

(B) Converting between unrelated pointer types.

(C) Upcasting (from derived to base).

(D) Downcasting (from base to derived) when you're certain of the object's actual type.

7. What happens when the only two shared_ptrs pointing to an object both go out of scope?

(A) Reference count goes to zero and the object is deleted.

(B) Reference count goes to 1 but the object remains.

(C) Undefined behavior occurs.

(D) The object is deleted twice.

8. Which of the following best describes the primary use of std::forward?

(A) To move ownership of resources.

(B) To cast values between unrelated types.

(C) To ensure that casing can only be done in one direction.

(D) To pass on arguments as they were provided to the calling function.

9. Which if the following is NOT a reason that assertions are helpful in your code?

(A) They can clearly identify that a problem exists before a regular crash or incorrect output occurs.

(B) They can be easily removed and thus have no negative impact on released code.

(C) They can be used to bring out-of-range function parameters back into range to restore code correctness.

(D) They will sometimes catch non-deterministic errors, helping you narrow down where they occurred.

(E) They interact well with debuggers, which help your trace back why an assertion failed.

10. Which of the following debugging techniques should typically be attempted only after the other techniques fail to help you resolve the issue?

(A) Add asserts to test pre- and post-conditions for functions that you expect to be involved.

(B) Add more related unit tests to understand the scope of your problem.

(C) Run your code through a debugger to see if it identifies the problem.

(D) Systematically remove (or comment out) sections of your program to find the minimal code that exhibits the problem.

(E) Fix all compiler warnings.