Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an older version of Boost and was released in 2024. The current version is 1.90.0.

Function combine

Function combine

The combine function is used to make one range from multiple ranges. The combine function returns a combined_range which is an iterator_range of a zip_iterator from the Boost.Iterator library.

Synopsis

namespace boost
{
    namespace range
    {

template<typename IterTuple>
class combined_range
    : public iterator_range<zip_iterator<IterTuple> >
{
public:
    combined_range(IterTuple first, IterTuple last);
};

template<typename... Ranges>
auto combine(Ranges&&... rngs) ->
    combined_range<decltype(boost::make_tuple(boost::begin(rngs)...))>

    } // namespace range
} // namespace boost

Precondition: For each type r in Ranges, r is a model of Single Pass Range or better.
Return Type: combined_range<tuple<typename range_iterator<Ranges>::type...> >
Returned Range Category: The minimum of the range category of every range r in Ranges.

Example

#include <boost/range/combine.hpp>
#include <boost/foreach.hpp>
#include <iostream>
#include <vector>
#include <list>

int main(int, const char*[])
{
    std::vector<int> v;
    std::list<char> l;
    for (int i = 0; i < 5; ++i)
    {
        v.push_back(i);
        l.push_back(static_cast<char>(i) + 'a');
    }

    int ti;
    char tc;
    BOOST_FOREACH(boost::tie(ti, tc), boost::combine(v, l))
    {
        std::cout << '(' << ti << ',' << tc << ')' << '\n';
    }

    return 0;
}

This produces the output:

(0,a)
(1,b)
(2,c)
(3,d)
(4,e)