C++ language

Question 1

C++: compile time type conversion

Answer 1

static_cast

Question 2

C++: down casting

Answer 2

dynamic_cast

Question 3

C++: modify the const or volatile qualifier of a variable

Answer 3

const_cast

Question 4

C++: converting a pointer to any other type of pointer

Answer 4

reinterpret_cast

Question 5

Which memory order has no ordering constraints on other reads or writes?

Answer 5

Relaxed

Question 6

Consumer memory order Constraints on consumer and release threads

Answer 6

Consumer: No read or writes dependent on the atomic value can be reordered before the load
Releaser: Writes to other data dependent variables are visible in the consumer thread

Question 7

Constraints on current and other threads for the acquire memory order

Answer 7

No reads or writes in the current thread can be reordered before this load
All writes in other threads that release this atomic variable are visible in the current thread

Question 8

Constraints of release memory order on current thread, an acquiring thread and a consuming thread

Answer 8

Current: No reads or writes can be reordered after the store
Acquirer: all previous writes from the releasing thread are visible to the acquiring thread
Consumer: previous writes that carry a dependency into the atomic variable from the releasing thread are visible to the consuming thread

Question 9

Three reasons why volatile cannot replace atomic access

Answer 9

May reorder past side effects as observed by another thread
May reorder other non volatile memory accesses
Not concurrent

Question 10

Four ways to pass an object to a function, and how it impacts the object ownership

Answer 10

Copy: Both
Reference: caller
Rvalue reference: callee
Forward reference: normal or rvalue reference

Question 11

Std::visit

Answer 11

Apply different functions to a variant object based on its current type

Question 12

C++ RVO: d2

Answer 12

Return value optimization
Eliminate unnecessary copy for returned object

Question 13

C++: pImpl Idiom - what, 2 benefits

Answer 13

Move private details into a separate structure
Compile time firewall
ABI stability

Question 14

Forward declaration: why, 4 uses, 2 not

Answer 14

Reduce compile time dependencies
Base classes, Member actual types
Pointer, reference, function parameter, function return

Question 15

Dependency injection: what

Answer 15

Technique in which an object or a function receives other objects and functions it needs, instead of creating them internally

Question 16

Dependency inversion pattern

Answer 16

Both higher and lower layers use abstractions to increase reuseability of higher layers

Question 17

Four execution policies

Answer 17

Sequenced, un sequenced, parallel, parallel unsequenced

Question 18

C++ algorithm for taking elements from one container to creating elements in another container

Answer 18

STD::transform

Question 19

What is an insert iterator

Answer 19

Calls the container’s insert method when assigned to

Question 20

C++ algorithm for filtering out elements from a range but don’t care about the order of the remaining elements

Answer 20

STD remove_if

Question 21

STD partition: 2 properties

Answer 21

C++ algorithm for dividing elements into two groups based on a condition and preserving the relative order within each group

Question 22

STD set_difference: what, how

Answer 22

Find differences between two sorted ranges
Copy elements from first range not in second range to output range

Question 23

4 meanings of f(x) in c++

Answer 23

Function call to f
A cast to type f
A function type
A declaration of x

Question 24

Std iota

Answer 24

Fill a range with sequentially increasing value

Question 25

aggregated struct: 4 criteria

Answer 25

No user defined constructors
No private or protected non static data members
No base classes
No virtual functions

Question 26

Aggregated structure: 2 benefits

Answer 26

Concise way to construct
More efficient to construct