| [section:filtered filtered] |
| |
| [table |
| [[Syntax] [Code]] |
| [[Pipe] [`rng | boost::adaptors::filtered(pred)`]] |
| [[Function] [`boost::adaptors::filter(rng, pred)`]] |
| ] |
| |
| * [*Precondition:] The `value_type` of the range is convertible to the argument type of `pred`. |
| * [*Postcondition:] For all adjacent elements `[x]` in the returned range, `pred(x)` is `true`. |
| * [*Throws:] Whatever the copy constructor of `pred` might throw. |
| * [*Range Category:] __forward_range__ |
| * [*Returned Range Category:] The minimum of the range category of `rng` and __bidirectional_range__ |
| |
| [section:filtered_example filtered example] |
| `` |
| #include <boost/range/adaptor/filtered.hpp> |
| #include <boost/range/algorithm/copy.hpp> |
| #include <boost/assign.hpp> |
| #include <algorithm> |
| #include <iostream> |
| #include <vector> |
| |
| struct is_even |
| { |
| bool operator()( int x ) const { return x % 2 == 0; } |
| }; |
| |
| int main(int argc, const char* argv[]) |
| { |
| using namespace boost::assign; |
| using namespace boost::adaptors; |
| |
| std::vector<int> input; |
| input += 1,2,3,4,5,6,7,8,9; |
| |
| boost::copy( |
| input | filtered(is_even()), |
| std::ostream_iterator<int>(std::cout, ",")); |
| } |
| `` |
| [endsect] |
| |
| This would produce the output: |
| `` |
| 2,4,6,8 |
| `` |
| [endsect] |
| |
| |