Multiple Choice Questions on C++20

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Major features introduced in C++20 are Spaceship operator, Modules, Concepts, Ranges, Coroutines, Calendar, Time zone, Constexpr, Span, Atomic_ref, Format, Tuple, Using etc.

Question: 1

Which C++ version support Digit Separators 1'000'000?

(A) C++11
(B) C++14
(C) C++17
(D) C++20

Level: Expert Category: cpp20

Question: 2

Which version of C++ added feature of auto for return type of functions?

(A) C++11
(B) C++14
(C) C++17
(D) C++20

Level: Expert Category: cpp20

Question: 3

In which version of C++ auto was limited to lambda functions?

(A) C++11
(B) C++14
(C) C++17
(D) C++20

Level: Expert Category: cpp20

Question: 4

#include <iostream>
#include <compare>

struct Point {
    int x;
    int y;

    auto operator<=>(const Point&) const = default;
};

int main() {
    Point p1{10, 4};
    Point p2{7, 5};

    // Compare using the spaceship operator
    std::strong_ordering result = p1 <=> p2;

    if (result == std::strong_ordering::less) {
        std::cout << "p1 is less than p2" << std::endl;
    } else if (result == std::strong_ordering::greater) {
        std::cout << "p1 is greater than p2" << std::endl;
    } else {
        std::cout << "p1 is equal to p2" << std::endl;
    }

    return 0;
}

(A) p1 is less than p2
(B) p1 is greater than p2
(C) p1 is equal to p2
(D) Compilation Error

Level: Experts Category: cpp20

Question: 5

#include <iostream>
#include <compare>

class Point {
public:    
    std::string x;
    int y;

    auto operator<=>(const Point&) const = default;
};

int main() {
    Point p1{"ABC", 4};
    Point p2{"ADC", 5};

    // Compare using the spaceship operator
    std::strong_ordering result = p1 <=> p2;

    if (result == std::strong_ordering::less) {
        std::cout << "p1 is less than p2" << std::endl;
    } else if (result == std::strong_ordering::greater) {
        std::cout << "p1 is greater than p2" << std::endl;
    } else {
        std::cout << "p1 is equal to p2" << std::endl;
    }

    return 0;
}

(A) p1 is less than p2
(B) p1 is greater than p2
(C) p1 is equal to p2
(D) Compilation Error

Level: Expert Category: cpp20

Question: 6

#include <iostream>
#include <bit>

int main() {
    unsigned int number = 129; 

    int count = std::popcount(number);

    std::cout << count << std::endl;

    return 0;
}

(A) 8
(B) 7
(C) 5
(D) 2

Level: Expert Category: cpp20

Question: 7

#include <iostream>
#include <vector>

int main() {

    std::vector<int> source = {1, 2, 3, 4, 5};

    std::vector<int> destination = std::move(source);

    std::cout << source.size() << ", " << destination.size();

    return 0;
}

(A) Compilation Error
(B) 5, 5
(C) 5, 0
(D) 0, 5

Level: Expert Category: cpp20

Question: 8

#include <iostream>
#include <string>


int main() {
   auto y = [] (auto first, auto second){
            return first + second;
   };
   
   auto z = [] (auto y, auto f, auto s){
            return y(f, s);
            
   };
   
   std::cout<<z(y, 5, 4);
   
    return 0;
}

(A) Compilation Error
(B) 0
(C) 9
(D) Linker Error

Level: Practionar Category: cpp20

Question: 9

What should be the output of following code?

#include <iostream>
#include <string>


int main() {
   auto glambda = [](auto a, auto&& b) { return a < b; };
   bool b = glambda(3, 3.14);
   std::cout<<b;
   
    return 0;
}

(A) True
(B) False
(C) 1
(D) Compilation Error

Level: Beginner Category: cpp20

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