C Plus Plus Miscellaneous — Part 1 MCQs with Explanations

In the given C++ code, the complex class from the C++ Standard Library is used to represent a complex number. In the statement complex cn(3.0, 5.0) , the constructor initializes the real part as 3.0 and the imaginary part as 5.0 . The function real(cn) returns the real part of the complex number, which is 3 . The function imag(cn) returns the imaginary part, which is 5 . Hence, the output will be: Complex number is: 3 + 5i .

The C++ code uses the STL functions sort() and next_permutation() to display permutations of a vector. Initially, the vector vi contains two elements: 3 and 5 . The sort(vi.begin(), vi.end()) function arranges the elements in ascending order, so the first output will be 3 5 . Then, the next_permutation() function rearranges the vector to the next lexicographical permutation, which will be 5 3 , and it is displayed after sorting. After this, there are no more permutations, so the loop terminates. Thus, the output will be: 5 3 3 5.

'++i' increments the value of 'i' before returning it, while 'i++' increments the value of 'i' after returning it is the correct answer to “What is the difference between '++i' and 'i++' in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

That the value of the variable cannot be changed is the correct answer to “What does the 'const' qualifier indicate in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To suggest the compiler to inline the function call is the correct answer to “What is the purpose of the 'inline' keyword in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To indicate that a variable may be modified by external factors is the correct answer to “What is the purpose of the 'volatile' qualifier in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

Using the 'const' keyword is the correct answer to “Which of the following is a valid way to initialize a constant variable in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To introduce a name from a namespace into the current scope is the correct answer to “What is the purpose of the 'using' directive in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

unsigned float is the correct answer to “Which of the following is not a valid C++ data type”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To return the type of an expression is the correct answer to “What is the purpose of the typeid operator in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

It allows the member function to modify the object's data members declared as const is the correct answer to “What does the mutable keyword in C++ mean when applied to a class member function”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

auto lambda = [](int x, int y) { return x + y; } is the correct answer to “Which of the following correctly defines a lambda function in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To perform explicit type conversions is the correct answer to “What is the purpose of the static_cast operator in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

int arr[5]; arr = {1, 2, 3, 4, 5} is the correct answer to “Which of the following is not a valid way to initialize an array in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

A null pointer value is the correct answer to “What does the nullptr keyword represent in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To cast an object to an rvalue reference is the correct answer to “What is the purpose of the std::move function in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To initialize containers with a list of values at compile time is the correct answer to “What is the purpose of the std::initializer_list class in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To indicate that a variable may be changed unexpectedly by hardware or another thread is the correct answer to “What is the purpose of the volatile keyword in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

ArrayList is the correct answer to “Which of the following is not a valid C++ standard library container”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

To specify that a variable's value cannot be changed once initialized is the correct answer to “What is the purpose of the const keyword in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

Resource Acquisition Is Initialization is the correct answer to “What does RAII stand for in C++”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

abstract class is the correct answer to “Which class is used to design the base class”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

0011 is the correct answer to “What will be the output of the following C++ code? #include <iostream> #include <limits> using namespace std; int main( ) { cout << numeric_limits<float> :: is_exact; cout << numeric_limits<double> :: is_exact; cout << numeric_limits<long int> :: is_exact; cout << numeric_limits<unsigned char> :: is_exact; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

base class only is the correct answer to “Where does the abstract class is used”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

Interface is the correct answer to “Which is the best design choice for using pointer to member function”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

ispunct() is the correct answer to “Which function is used to check whether a character is punctuation mark”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

norm() is the correct answer to “Which function is used to calculate the norm of a complex number”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

10000010 is the correct answer to “What will be the output of the following C++ code? #include <iostream> #include <cctype> using namespace std; int main(int argc, char const *argv[]) { char arr[20] = "\'H3ll0\'"; for(int i=0;i<8;i++) { cout<<(bool)ispunct(arr[i]); } }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

get<0>(Arr) is the correct answer to “What is the syntax of printing the first element of an array Arr using get() function”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

1 2 3 4 5 6 7 8 9 10 is the correct answer to “What will be the output of the following C++ code? #include <iostream> #include <vector> #include <forward_list> using namespace std; int main() { forward_list<int> fl1 = {1,7,8,9,10}; forward_list<int> fl2 = {2,3,4,5,6}; fl1.splice_after(fl1.begin(), fl2); for (int&c : fl1) cout << c << " "; cout<<endl; return 0; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

Multimap can have same keys whereas the map cannot is the correct answer to “Which of the following is correct about map and multimap”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

All of the mentioned is the correct answer to “Which of the following is correct about Input Iterators”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

1 1 1 2 is the correct answer to “What will be the output of the following C++ code? #include <iostream> #include <functional> #include <numeric> using namespace std; int myop (int x, int y) { return x + y; } int main () { int val[] = {1, 2, 3, 5}; int result[7]; adjacent_difference (val, val + 7, result); for (int i = 0; i < 4; i++) cout << result[i] <<' '; return 0; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

Insertion in vectors always takes constant time is the correct answer to “Pick the incorrect statement.”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

D1::function1() and Base::function2() is the correct answer to “Given below classes which of the following are the possible row entries in vtable of D1 class? class Base { public: virtual void function1() {}; virtual void function2() {}; }; class D1: public Base { public: virtual void function1() {}; }; class D2: public Base { public: virtual void function2() {}; };”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

10 is the correct answer to “What will be the capacity of the vector after 10 is pushed into the vector in the following C++ code? #include <iostream> #include <vector> using namespace std; int main() { vector<int> v; for (int i = 1; i <= 5; i++) v.push_back(i); cout<<v.capacity()<<endl; v.shrink_to_fit(); cout<<v.capacity()<<endl; v.push_back(10); return 0; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

<random> is the correct answer to “Which header file is used for generating random numbers”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

10 100 is the correct answer to “What will be the output of the following C++ code? #include<iostream> using namespace std; class X { int m; public: X() : m(10) { } X(int mm): m(mm) { } int getm() { return m; } }; class Y : public X { int n; public: Y(int nn) : n(nn) {} int getn() { return n; } }; int main() { Y yobj( 100 ); cout << yobj.getm() << " " << yobj.getn() << endl; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

10100000 01111111 00001101 is the correct answer to “What will be the output of the following C++ code? #include <iostream> #include <bitset> using namespace std; int main() { bitset<8> b1(95); bitset<8> b2(45); cout<<~b1<<endl; cout<<(b1|b2)<<endl; cout<<(b1&b2)<<endl; }”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.

isdigit() is the correct answer to “Which function is used to check whether a character is a number”. This question is standard in competitive examination syllabi for C Plus Plus Miscellaneous.