C++ Brain Teasers: Exercise Your Mind/

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Discussion: Monsters on the Move

Discussion: Monsters on the Move

Execute the code to understand the output and gain insights into constructor behavior and value categories.

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Run the code

Now, it’s time to execute the code and observe the output.

C++ 17
#include <iostream>
struct Monster
{
    Monster() = default;
    Monster(const Monster &other)
    {
        std::cout << "Monster copied\n";
    }
    Monster(Monster &&other)
    {
        std::cout << "Monster moved\n";
    }
};
struct Jormungandr : public Monster
{
    Jormungandr() = default;
    Jormungandr(const Jormungandr &other) : Monster(other)
    {
        std::cout << "Jormungandr copied\n";
    }
    Jormungandr(Jormungandr &&other) : Monster(other)
    {
        std::cout << "Jormungandr moved\n";
    }
};
int main()
{
    Jormungandr jormungandr1;
    Jormungandr jormungandr2{std::move(jormungandr1)};
}

Understanding the output

When we initialize the second Jormungandr with a moved-from object, the move constructor gets called for Jormungandr but the copy constructor for Monster. Why is that?

As we learned in the ...