1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___ALGORITHM_COUNT_IF_H
11#define _LIBCPP___ALGORITHM_COUNT_IF_H
12
13#include <__config>
14#include <__iterator/iterator_traits.h>
15
16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17#  pragma GCC system_header
18#endif
19
20_LIBCPP_BEGIN_NAMESPACE_STD
21
22template <class _InputIterator, class _Predicate>
23_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
24    typename iterator_traits<_InputIterator>::difference_type
25    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
26  typename iterator_traits<_InputIterator>::difference_type __r(0);
27  for (; __first != __last; ++__first)
28    if (__pred(*__first))
29      ++__r;
30  return __r;
31}
32
33_LIBCPP_END_NAMESPACE_STD
34
35#endif // _LIBCPP___ALGORITHM_COUNT_IF_H
36