[/
    Copyright 2010 Neil Groves
    Distributed under the Boost Software License, Version 1.0.
    (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
/]
[section:count count]

[heading Prototype]

``
template<class SinglePassRange, class Value>
typename range_difference<SinglePassRange>::type
count(SinglePassRange& rng, const Value& val);

template<class SinglePassRange, class Value>
typename range_difference<const SinglePassRange>::type
count(const SinglePassRange& rng, const Value& val);
``

[heading Description]

`count` returns the number of elements `x` in `rng` where `x == val` is `true`.

[heading Definition]

Defined in the header file `boost/range/algorithm/count.hpp`

[heading Requirements]

* `SinglePassRange` is a model of the __single_pass_range__ Concept.
* `Value` is a model of the `EqualityComparableConcept`.
* `SinglePassRange`'s value type is a model of the `EqualityComparableConcept`.
* An object of `SinglePassRange`'s value type can be compared for equality with an object of type `Value`.

[heading Complexity]

Linear. Exactly `distance(rng)` comparisons.

[endsect]