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 2013. The current version is 1.90.0.

indexed

indexed

indexed example

Syntax	Code
Pipe	`rng \| boost::adaptors::indexed(start_index)`
Function	`boost::adaptors::index(rng, start_index)`

Returns: A range adapted to return both the element and the associated index. The returned range consists of iterators that have in addition to the usual iterator member functions an index() member function that returns the appropriate index for the element in the sequence corresponding with the iterator.
Range Category: Single Pass Range
Range Return Type: boost::indexed_range<typeof(rng)>
Returned Range Category: The range category of rng

indexed example

#include <boost/range/adaptor/indexed.hpp>
#include <boost/range/algorithm/copy.hpp>
#include <boost/assign.hpp>
#include <iterator>
#include <iostream>
#include <vector>

template<class Iterator>
void display_element_and_index(Iterator first, Iterator last)
{
    for (Iterator it = first; it != last; ++it)
    {
        std::cout << "Element = " << *it << " Index = " << it.index() << std::endl;
    }
}

template<class SinglePassRange>
void display_element_and_index(const SinglePassRange& rng)
{
    display_element_and_index(boost::begin(rng), boost::end(rng));
}

int main(int argc, const char* argv[])
{
    using namespace boost::assign;
    using namespace boost::adaptors;

    std::vector<int> input;
    input += 10,20,30,40,50,60,70,80,90;

    display_element_and_index( input | indexed(0) );

    return 0;
}

This would produce the output:

Element = 10 Index = 0
Element = 20 Index = 1
Element = 30 Index = 2
Element = 40 Index = 3
Element = 50 Index = 4
Element = 60 Index = 5
Element = 70 Index = 6
Element = 80 Index = 7
Element = 90 Index = 8