Boost范围库：按顺序遍历两个范围 [英] Boost Range Library: Traversing Two Ranges Sequentially

问题描述

Boost范围库（ http：//www.boost。 org / doc / libs / 1_35_0 / libs / range / index.html ）允许我们将一对迭代器抽象为一个范围。现在我想将两个范围合并为一个，即：

Boost range library (http://www.boost.org/doc/libs/1_35_0/libs/range/index.html) allows us to abstract a pair of iterators into a range. Now I want to combine two ranges into one, viz:

给定两个范围r1和r2，定义r遍历[r1.begin（），r1.end [然后[r2.begin（），r2.end（）[。有什么方法可以使用r1和r2将r定义为范围？

given two ranges r1 and r2, define r which traverses [r1.begin(), r1.end()[ and then [r2.begin(), r2.end()[. Is there some way to define r as a range using r1 and r2?

推荐答案

。有一种方法使用boost / range / join.hpp来连接两个范围。不幸的输出范围类型不包括在界面中：

I needed this again so I had a second look. There is a way to concat two ranges using boost/range/join.hpp. Unluckily the output range type is not included in the interface:

#include "boost/range/join.hpp"
#include "boost/foreach.hpp"
#include <iostream>

int main() {
        int a[] = {1, 2, 3, 4};
        int b[] = {7, 2, 3, 4};

        boost::iterator_range<int*> ai(&a[0], &a[4]);
        boost::iterator_range<int*> bi(&b[0], &b[4]);
        boost::iterator_range<
           boost::range_detail::
           join_iterator<int*, int*, int, int&, 
           boost::random_access_traversal_tag> > ci = boost::join(ai, bi); 

        BOOST_FOREACH(int& i, ci) {
                std::cout << i; //prints 12347234
        }
}

编译器消息。 C ++ 0x auto 也会在那里相关。

I found the output type using the compiler messages. C++0x auto will be relevant there as well.

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