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151.

Indexing of bitset variables starts from ___________(a) leftmost bit(b) rightmost bit(c) same as in an array(d) frontThis question was addressed to me in an online interview.Question is taken from Bitset topic in division Class Hierarchies, Library & Containers of C++

Answer» RIGHT OPTION is (B) rightmost bit

The explanation: The indexing of bitset variable starts from rightmost bit i.e. if you have b = 1100 as your bitset then b[0] = 0, not 1.
Discussion
152.

What is vptr?(a) A hidden pointer in a class that points to a virtual table of that class(b) A hidden pointer in a class that points to virtual functions of that class(c) A hidden pointer in a class that points to virtual members of the class of that class(d) A pointer in a class that points to other classI got this question in quiz.My question is taken from vtable and vptr topic in section Class Hierarchies, Library & Containers of C++

Answer»

Correct ANSWER is (a) A hidden POINTER in a CLASS that points to a virtual table of that class

The best I can EXPLAIN: vptr is a hidden pointer available with classes which are used to POINT to the virtual table of a class.
Discussion
153.

Which function is used to get the argument of a complex number?(a) abs()(b) norm()(c) arg()(d) argu()This question was posed to me by my school teacher while I was bunking the class.My doubt stems from Complex Library in chapter Class Hierarchies, Library & Containers of C++

Answer» RIGHT answer is (c) ARG()

The BEST I can explain: The argument of a complex is calculated using the arg() function of the HEADER.
Discussion
154.

Which of the following function is used to get the actual number of elements stored in vector?(a) v.size()(b) v.capacity()(c) v.max_size()(d) v.no_of_elements()The question was asked by my college director while I was bunking the class.Origin of the question is seq_con Vector Class topic in portion Class Hierarchies, Library & Containers of C++

Answer»

The correct answer is (a) V.size()

Explanation: To get the number of elements stored in the vector v we use the function v.size(). It returns how many elements are CURRENTLY in the vector excluding the VOID places.
Discussion
155.

What is Pseudo-random number engines?(a) Uses user input for random number generation(b) Uses an algorithm that does not require any initial seed to generate random numbers(c) Uses initial seed based algorithm to generate random numbers(d) Random number generates depends on the programThis question was posed to me in an interview.Enquiry is from Generators in section Class Hierarchies, Library & Containers of C++

Answer» CORRECT option is (c) Uses initial SEED based algorithm to generate random numbers

To explain I would say: Pseudo-random NUMBER engines are used to generate random numbers based on an initial seed provided to them.
Discussion
156.

Which is best for coding the standard library for c++?(a) no trailing underscores on names(b) complex objects are returned by value(c) have a member-swap()(d) all of the mentionedI had been asked this question at a job interview.My enquiry is from Standard Library Design topic in division Class Hierarchies, Library & Containers of C++

Answer» RIGHT choice is (d) all of the mentioned

The best explanation: Best coding for the standard LIBRARY for c++ is:

-> No trailing UNDERSCORES on names

-> Complex OBJECTS are returned by VALUE

-> It should have a member-swap().
Discussion
157.

What is the full form of vtable?(a) V type table(b) Vector table(c) Virtual table(d) Virtual-vector tableThe question was asked in quiz.Query is from vtable and vptr topic in portion Class Hierarchies, Library & Containers of C++

Answer»

Right ANSWER is (C) VIRTUAL table

Easiest explanation - Full form of vtable is a virtual table. This is called so because it STORES the information about virtual functions of a class.
Discussion
158.

Which operator is used to create the user-defined streams in c++?(a) >>(b) &

Answer»

Correct OPTION is (d) Both >> & <<

Explanation: We can make user-defined types with STREAMS by OVERLOADING the insertion operator (<<) to put OBJECTS into streams and the extraction operator (>>) to read objects from streams.
Discussion
159.

Which function is used to check whether a given sequence is heap or not?(a) sort_heap()(b) is_heap()(c) is_heap_until()(d) check_heap()The question was posed to me in semester exam.I need to ask this question from STL topic in division Class Hierarchies, Library & Containers of C++

Answer»

The CORRECT answer is (b) is_heap()

The best explanation: C++ STL-heap container provides is_heap() function to check whether a given SEQUENCE of elements represents a heap or not. Descending order of elements represents a valid heap.
Discussion
160.

Elements in STL heap are removed in ________________________(a) decreasing order(b) increasing order(c) alternate i.e. once max element then min element(d) input orderI had been asked this question in an internship interview.Query is from STL topic in chapter Class Hierarchies, Library & Containers of C++

Answer»

Right choice is (a) decreasing order

Easy EXPLANATION - C++ STL-heap SIMULATES the MAX heap i.e. the maximum ELEMENT is at the top/front of the heap hence on poping we pop the first element which is always the maximum number in the sequence.
Discussion
161.

Which of the following(s) can be used to access the first element of a vector v?(a) v.begin()(b) v.cbegin()(c) v[0](d) all of the mentionedI got this question in a job interview.Query is from seq_con Vector Class in portion Class Hierarchies, Library & Containers of C++

Answer»

Correct option is (d) all of the mentioned

The best explanation: To ACCESS the first element of a VECTOR we can USE the following THINGS:

i) v.begin()

ii) v.cbegin()

iii) v[0]

iv) v.at(0)
Discussion
162.

Which of the following class template are based on arrays?(a) vector(b) list(c) dequeue(d) both vector & dequeueThe question was asked in semester exam.I would like to ask this question from Sequences in division Class Hierarchies, Library & Containers of C++

Answer» CORRECT choice is (d) both vector & DEQUEUE

To explain: Class template vector and class template dequeue both are BASED on arrays.
Discussion
163.

Which interface in the container is required for storage management?(a) Memory management(b) Allocator interface(c) Memory interface(d) Storage interfaceThis question was posed to me in homework.My question comes from Container Design in portion Class Hierarchies, Library & Containers of C++

Answer» CORRECT answer is (b) ALLOCATOR interface

Explanation: Allocator interface in the CONTAINER is REQUIRED for storage management.
Discussion