迭代器上是否有一个STL适配器为每个集合元素调用回调？

I am especially interested in adaptor for a following use case:

我对以下用例的适配器特别感兴趣:

std::list<int> input {1, 2, 3};
std::list<int> result;
auto l = [](auto e) { return e + 1; };
result.insert(result.end(), adaptor(input.begin(), l), adaptor(input.end(), l));
// now result == {2, 3, 4}

It would be nice if the adaptor would not use external libraries (e.g. boost).

如果适配器不使用外部库(例如boost)会很好。

2 个解决方案

#1

Your question is tagged C++14, and says that no external library dependence would be great (fair enough).

你的问题被标记为C ++ 14,并且说没有外部库依赖会很好(足够公平)。

For future reference, though, note that the range library seems well on its way toward adoption by the standard library (the C++17 range for loop is already compliant with one of its major points). So, using range, the code could look like this:

但是,为了将来参考,请注意,范围库似乎正在向标准库采用(C ++ 17 range for loop已经符合其主要要点之一)。因此,使用范围,代码可能如下所示:

#include <list>
#include <range/v3/all.hpp>

int main() {
    const std::list<int> input{1, 2, 3};
    const std::list<int> result = 
        input | ranges::view::transform([](int i){ return i + 1; });
}

and it's what future standard library C++ code is likely to be. Irrespectively, it has its advantages:

这就是未来标准库C ++代码的可能性。无论如何,它有其优点:

It looks more intuitive (although that might be subjective).

它看起来更直观(虽然这可能是主观的)。
Note how you can make result const.

注意如何使结果const。

#2

So using PiotrSkotnicki advice I end up with a code like this:

所以使用PiotrSkotnicki建议我最终得到这样的代码:

#include <algorithm>
#include <iterator>
#include <list>

int main() {
   std::list<int> input {1, 2, 3};
   std::list<int> output;
   std::transform(input.begin(), input.end(), std::back_inserter(output), [](auto e){ return e + 1;});
}

#1