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 
22 template <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