B1

gistfile1.txt

template <typename SourceIterator, typename DestinationIterator, typename Predicate>
DestinationIterator copy_backward_if(SourceIterator source_first, SourceIterator source_last, DestinationIterator destination_last, Predicate condition) {
    while (source_last != source_first) {
        if (condition(*source_first)) {
            *(--destination_last) = *source_first;
        }
        ++source_first;
    }
    return destination_last;
}