boost_1_45_0/libs/range/doc/reference/algorithm/equal.qbk

[section:equal equal]

[heading Prototype]

``
template<
    class SinglePassRange1,
    class SinglePassRange2
>
bool equal(const SinglePassRange1& rng1,
           const SinglePassRange2& rng2);

template<
    class SinglePassRange1,
    class SinglePassRange2,
    class BinaryPredicate
>
bool equal(const SinglePassRange1& rng1,
           const SinglePassRange2& rng2,
           BinaryPredicate         pred);
``

[heading Description]

`equal` returns `true` if `distance(rng1)` is equal to the `distance(rng2)` and for each element `x` in `rng1`, the corresponding element `y` in `rng2` is equal. Otherwise `false` is returned.

In this range version of `equal` it is perfectly acceptable to pass in two ranges of unequal lengths.

Elements are considered equal in the non-predicate version if `operator==` returns `true`. Elements are considered equal in the predicate version if `pred(x,y)` is `true`.

[heading Definition]

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

[heading Requirements]

[*For the non-predicate versions:]

* `SinglePassRange1` is a model of the __single_pass_range__ Concept.
* `SinglePassRange2` is a model of the __single_pass_range__ Concept.
* `SinglePassRange1`'s value type is a model of the `EqualityComparableConcept`.
* `SinglePassRange2`'s value type is a model of the `EqualityComparableConcept`.
* `SinglePassRange1`'s value type can be compared for equality with `SinglePassRange2`'s value type.

[*For the predicate versions:]

* `SinglePassRange1` is a model of the __single_pass_range__ Concept.
* `SinglePassRange2` is a model of the __single_pass_range__ Concept.
* `BinaryPredicate` is a model of the `BinaryPredicateConcept`.
* `SinglePassRange1`'s value type is convertible to `BinaryPredicate`'s first argument type.
* `SinglePassRange2`'s value type is convertible to `BinaryPredicate`'s second argument type.

[heading Complexity]

Linear. At most `min(distance(rng1), distance(rng2))` comparisons.

[endsect]