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https://github.com/bolero-MURAKAMI/Sprout.git
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28 lines
699 B
C++
28 lines
699 B
C++
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#ifndef SPROUT_DETAIL_COUNT_N_IF_HPP
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#define SPROUT_DETAIL_COUNT_N_IF_HPP
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#include <iterator>
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#include <sprout/config.hpp>
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#include <sprout/iterator/operation.hpp>
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namespace sprout {
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namespace detail {
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//
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// count_n_if
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//
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template<typename InputIterator, typename Size, typename Predicate>
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SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type count_n_if(
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InputIterator first,
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Size n,
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Predicate pred
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)
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{
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return n == 0 ? 0
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: (pred(*first) ? 1 : 0) + sprout::detail::count_n_if(sprout::next(first), n - 1, pred)
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;
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}
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} // namespace detail
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} // namespace sprout
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#endif // #ifndef SPROUT_DETAIL_COUNT_N_IF_HPP
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