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Sprout/docs/_sources/libs/algorithm/count.txt

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.. _sprout-algorithm-count:
2014-08-15 12:27:31 +00:00
###############################################################################
count
###############################################################################
Interface
========================================
.. sourcecode:: c++
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR typename std::iterator_traits<InputIterator>::difference_type
count(InputIterator first, InputIterator last, T const& value);
Returns
========================================
| The number of iterators i in the range [first,last) for which the following corresponding conditions hold: ``*i == value``.
Examples
========================================
.. sourcecode:: c++
#include <sprout/algorithm/count.hpp>
#include <sprout/array.hpp>
#include <sprout/container.hpp>
using namespace sprout;
SPROUT_STATIC_CONSTEXPR auto input = array<int, 10>{{1, 2, 3, 5, 5, 5, 5, 8, 9, 10}};
SPROUT_STATIC_CONSTEXPR auto result = sprout::count(begin(input), end(input), 5);
static_assert(result == 4, "counted 4 elements equal to 5 from input.");
Complexity
========================================
| Exactly ``last - first`` applications of the predicate.
| Recursive function invocations in *O(logN)* (logarithmic) depth.
Header
========================================
| ``sprout/algorithm/count.hpp``
| Convenience header: ``sprout/algorithm.hpp``