本文介绍了C ++ 11反向基于范围的for-loop的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有一个容器适配器会颠倒迭代器的方向,所以我可以反过来使用基于范围的for-loop迭代容器。
Is there a container adapter that would reverse the direction of iterators so I can iterate over a container in reverse with range-based for-loop?
使用显式迭代器我会转换这个:
With explicit iterators I would convert this:
for (auto i = c.begin(); i != c.end(); ++i) { ...
:
for (auto i = c.rbegin(); i != c.rend(); ++i) { ...
我要转换:
for (auto& i: c) { ...
到此:
for (auto& i: std::magic_reverse_adapter(c)) { ...
有没有这样的事情,还是我自己写的?
Is there such a thing or do I have to write it myself?
推荐答案
Actually Boost确实有这样的适配器:。
Actually Boost does have such adaptor: boost::adaptors::reverse
.
#include <list>
#include <iostream>
#include <boost/range/adaptor/reversed.hpp>
int main()
{
std::list<int> x { 2, 3, 5, 7, 11, 13, 17, 19 };
for (auto i : boost::adaptors::reverse(x))
std::cout << i << '\n';
for (auto i : x)
std::cout << i << '\n';
}
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