template<class InputIterator, class T = iterator_traits<InputIterator>::value_type>
constexpr typename iterator_traits<InputIterator>::difference_type
count(InputIterator first, InputIterator last, const T& value);
template<class ExecutionPolicy, class ForwardIterator,
class T = iterator_traits<ForwardIterator>::value_type>
typename iterator_traits<ForwardIterator>::difference_type
count(ExecutionPolicy&& exec,
ForwardIterator first, ForwardIterator last, const T& value);
template<class InputIterator, class Predicate>
constexpr typename iterator_traits<InputIterator>::difference_type
count_if(InputIterator first, InputIterator last, Predicate pred);
template<class ExecutionPolicy, class ForwardIterator, class Predicate>
typename iterator_traits<ForwardIterator>::difference_type
count_if(ExecutionPolicy&& exec,
ForwardIterator first, ForwardIterator last, Predicate pred);
template<input_iterator I, sentinel_for<I> S, class Proj = identity,
class T = projected_value_t<I, Proj>>
requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
constexpr iter_difference_t<I>
ranges::count(I first, S last, const T& value, Proj proj = {});
template<input_range R, class Proj = identity, class T = projected_value_t<iterator_t<R>, Proj>>
requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
constexpr range_difference_t<R>
ranges::count(R&& r, const T& value, Proj proj = {});
template<input_iterator I, sentinel_for<I> S, class Proj = identity,
indirect_unary_predicate<projected<I, Proj>> Pred>
constexpr iter_difference_t<I>
ranges::count_if(I first, S last, Pred pred, Proj proj = {});
template<input_range R, class Proj = identity,
indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
constexpr range_difference_t<R>
ranges::count_if(R&& r, Pred pred, Proj proj = {});