[section:find_if find_if]

[heading Prototype]

``
template<class SinglePassRange, class UnaryPredicate>
typename range_iterator<SinglePassRange>::type
find_if(SinglePassRange& rng, UnaryPredicate pred);

template<
    range_return_value re,
    class SinglePassRange,
    class UnaryPredicate
    >
typename range_return<SinglePassRange, re>::type
find_if(SinglePassRange& rng, UnaryPredicate pred);
``

[heading Description]

The versions of `find_if` that return an iterator, returns the first iterator in the range `rng` such that `pred(*i)` is `true`. `end(rng)` is returned if no such iterator exists.

The versions of `find_if` that return a `range_return`, defines found in the same manner as the returned iterator described above.

[heading Definition]

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

[heading Requirements]

* `SinglePassRange` is a model of the __single_pass_range__ Concept.
* `UnaryPredicate` is a model of the `PredicateConcept`.
* The value type of `SinglePassRange` is convertible to the argument type of `UnaryPredicate`.

[heading Precondition:]

For each iterator `i` in `rng`, `*i` is in the domain of `UnaryPredicate`.

[heading Complexity]

Linear. At most `distance(rng)` invocations of `pred`.

[endsect]