Multiple Choice Quiz

1. If a variable is declared as constexpr, will its value be set at compile time?

(A) Yes, always

(B) Only if you set the compiler to use optimizations

(C) Only if it is also marked static

(D) Usually, but it is up to the compiler and the programmer can never guarantee that it will.

(E) Usually, but it is only guaranteed if the value is used elsewhere at compile time

2. How do move semantics contribute to the efficiency of classes with value semantics?

(A) They eliminate the need to manually define destructors as resources are recycled instead of freed.

(B) They enable the compiler to inline all member functions automatically.

(C) They enforce deep copies to avoid the need to ever share resources.

(D) They guarantee that no actual copies will ever occur.

(E) They allow the resources of temporary objects to be transferred rather than copied.

3. If you want to use value semantics on objects of a custom class, which of the following is most important to implement?

(A) A friend class

(B) A copy constructor

(C) A default constructor

(D) An operator<< for printing

(E) A virtual destructor

4. Which standard C++ library provides time-based tools that can be used for benchmarking?

(A) <chrono>

(B) <measure>

(C) <record>

(D) <metrics>

(E) <snapshot>

5. What is a common pitfall when writing a microbenchmark in C++?

(A) The operating system may require the code to be compiled in debug mode.

(B) Clocks are only guaranteed to be accurate to the second, while many tests you need to time will be much faster than that.

(C) Activating the timing code may alter how the CPU processes instructions, altering the algorithms being tested.

(D) The compiler might optimize away the code being benchmarked if its results are not used.

(E) The use of <chrono> may introduce significant overhead in the timing measurements.

6. What is the standard way to implement custom memory allocation in C++?

(A) Via the constructor and destructor of each class you want to customize

(B) By replacing the new and delete operators

(C) By replacing the malloc and free functions

(D) You cannot implement custom global memory management

7. Which of the following factors would make it impossible to effectively profile a function?

(A) Code marked constexpr, since we don't know if it will run at compile-time or run-time

(B) Exceptions, since they may radically change the flow of code

(C) Virtual functions, since we may not know which version of a function will be run

(D) Lambdas, because they don't have a pre-defined type

(E) User interaction, especially code that needs to wait for a user response

8. Many std::string implementations maintain an instance of the empty string rather than just using a null pointer. Why?

(A) It reduces the amount of memory needed to maintain strings.

(B) It eliminates the need for a conditional to test if the string is empty.

(C) The use of null pointers is fundamentally a bad programming practice.

(D) It provides a built-in mechanism for overloading operators specifically for empty strings.

(E) It allows empty strings to be garbage collected, reducing memory leaks.

9. What is small string optimization?

(A) Handling small strings in existing space without allocating extra memory

(B) Dedicating heap space to optimize empty strings ("")

(C) Splitting longer strings into multiple shorter substrings, with some substrings being shared

(D) Handling small strings using preallocated memory shared among strings

(E) Compressing strings to require less memory

10. How does if constexpr differ from a regular if statement?

(A) Only the branch whose condition is a compile-time constant and evaluates to true is compiled.

(B) It requires that both branches can be fully evaluated at compile time, similar to a constexpr function.

(C) It allows dynamic evaluation of conditions during either compile time or runtime, depending on the inputs.

(D) Both branches are compiled, but the result of the condition is pre-calculated at compile-time.

(E) It only accepts integer constant expressions for its condition.