Questions / Quant development, C++ ownership & memory
An alias can own more than it points at
In C++17, all allocations succeed. What is printed after owner.reset()?
auto owner = std::make_shared<std::array<int, 2>>(std::array<int, 2>{9, 14});
std::shared_ptr<int> part(owner, &(*owner)[1]);
owner.reset();
std::cout << *part;Answer it in the app It's free. You get hints, a second try if you miss, and a follow-up question.
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Answer: 14 value
- part shares ownership of the entire array with owner while storing the address of its second element. Resetting owner leaves part as an owner, so the array remains alive and *part is 14.
Interview shortcut. The aliasing constructor shares ownership of the whole array.
In the app this has a follow-up where one thing about the setup changes. Try the follow-up.