Convert containers via constructor

Question

Suppose I have classes

class A {
   //...
};

struct B {
   explicit B(const A&);
   //...
};

and I have a container of A's, from which I would like to construct a container of B's. What is an idiomatic way to do this in c++ 03?

Tried and failed:

std::vector<A> source = fillSourceObjects();
std::vector<B> target;

// 1) won't compile; presumably I need a static helper function, 
//    but I would like to avoid that
std::transform(source.begin(), source.end(), std::back_inserter(target), B);
std::transform(source.begin(), source.end(), std::back_inserter(target), B::B);

// 2) won't compile; "... error: no match for 'operator=' in '* __result = *__first'
std::copy(source.begin(), source.end(), target.begin());

Answer 1

您可以使用带有序列的std::vector<T>构造函数将A s序列转换为B s序列：

std::vector<B> target(source.begin(), source.end());