在std :: bitset和std :: vector< bool>之间转换 [英] Converting Between std::bitset and std::vector<bool>

问题描述

我有一个std::bitset，但是现在我想在其上使用STL算法.

I have a std::bitset but now I want to use an STL algorithm on it.

本来可以使用std::vector<bool>，但是我喜欢std::bitset的构造函数，并且我希望std::bitset的按位运算.

I could have used std::vector<bool> instead, but I like std::bitset's constructor and I want std::bitset's bitwise operations.

我是否必须经过循环并将所有内容填充到std::vector<bool>中才能使用STL算法，然后将其复制回std::bitset，还是有更好的方法?

Do I have to go through a loop and stuff everything in a std::vector<bool> to use STL algorithms, and then copy that back to the std::bitset, or is there a better way?

推荐答案

Matthew Austern在此处为bitset写了一个迭代器:

Matthew Austern wrote an iterator for bitset here: http://www.drdobbs.com/the-standard-librarian-bitsets-and-bit-v/184401382?pgno=2

它超过100行，所以我觉得只是将其抬起并放入答案中可能有点超出范围.但是它对于STL算法非常有用.

It's over 100 lines so I feel just lifting it and putting it in this answer may be a bit out of bounds. But it works marvelously for STL algorithms.

澳大利亚人回答了这个确切的问题:

Austern answers this exact question:

虽然位集没有STL容器接口，但它仍然是一个非常好的(固定大小)容器.如果使用位集对您有意义，并且还需要迭代器，则可以定义一个简单的索引迭代器"适配器，将* i等迭代器符号转换为b [n]等数组符号.该实现非常简单:维护一个索引和一个指向容器的指针.

While bitset doesn’t have the STL container interface, it’s still a perfectly good (fixed-size) container. If it makes sense for you to use a bitset, and if you also need iterators, then you can define a simple "index iterator" adaptor that translates iterator notation like *i into array notation like b[n]. The implementation is straightforward: maintain an index and a pointer to a container.

他确实警告了迭代器:

如果我们愿意接受稍微麻烦一些的接口，则可以定义一个类，该类适用于任意类似数组的类型.通用索引迭代器适配器在处理STL之前的容器类时有时甚至在处理诸如vector之类的STL容器时通常很有用.

If we were willing to accept a slightly more cumbersome interface, we could define a class that worked with arbitrary array-like types. A general purpose index iterator adaptor is often useful when dealing with pre-STL container classes, and sometimes even when dealing with STL containers like vector.

还应注意，与vector<bool>::iterator一样，Austern的bitset_iterator::operator*不会返回bool&，而是返回代理引用:bitset<>::reference.

It should also be noted that just as with a vector<bool>::iterator, Austern's bitset_iterator::operator* doesn't return a bool& but a proxy reference: bitset<>::reference.

bitset_iterator的用法如下:

std::bitset<10> foo;
std::vector<bool> bar(begin(foo), end(foo));

这篇关于在std :: bitset和std :: vector< bool>之间转换的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！