如何使用算法将一个容器中的对象中的成员复制到另一个容器？

Question

I have a container of objects and I would like to copy the same member from each object to a container of that member's type.

Ie Something like this:

struct X { int x; }

std::vector<X> src;
std::vector<int> dst;

...

auto it_dst = dst.begin();
for (auto& element : src) {
  *(it_dst++) = element.x;
}

Of course, using an algorithm and not a for loop.

Answer 1

Seems like a job for transform with a lambda (I consider you haven't allocated your vector):

std::transform(src.begin(), src.end(), std::back_inserter(dst),
               [](const auto& v) -> int { return v.x; });