`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.
