1[/
2    Copyright 2010 Neil Groves
3    Distributed under the Boost Software License, Version 1.0.
4    (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5/]
6[section:lexicographical_compare lexicographical_compare]
7
8[heading Prototype]
9
10``
11template<
12    class SinglePassRange1,
13    class SinglePassRange2
14    >
15bool lexicographical_compare(const SinglePassRange1& rng1,
16                             const SinglePassRange2& rng2);
17
18template<
19    class SinglePassRange1,
20    class SinglePassRange2,
21    class BinaryPredicate
22    >
23bool lexicographical_compare(const SinglePassRange1& rng1,
24                             const SinglePassRange2& rng2,
25                             BinaryPredicate pred);
26``
27
28[heading Description]
29
30`lexicographical_compare` compares element by element `rng1` against `rng2`. If the element from `rng1` is less than the element from `rng2` then `true` is returned. If the end of `rng1` without reaching the end of `rng2` this also causes the return value to be `true`. The return value is `false` in all other circumstances. The elements are compared using `operator<` in the non-predicate versions of `lexicographical_compare` and using `pred` in the predicate versions.
31
32[heading Definition]
33
34Defined in the header file `boost/range/algorithm/lexicographical_compare.hpp`
35
36[heading Requirements]
37
38[*For the non-predicate versions of lexicographical_compare:]
39
40* `SinglePassRange1` is a model of the __single_pass_range__ Concept.
41* `SinglePassRange2` is a model of the __single_pass_range__ Concept.
42* `SinglePassRange1`'s value type is a model of the `LessThanComparableConcept`.
43* `SinglePassRange2`'s value type is a model of the `LessThanComparableConcept`.
44* Let `x` be an object of `SinglePassRange1`'s value type. Let `y` be an object of `SinglePassRange2`'s value type. `x < y` must be valid. `y < x` must be valid.
45
46[*For the predicate versions of lexicographical_compare:]
47
48* `SinglePassRange1` is a model of the __single_pass_range__ Concept.
49* `SinglePassRange2` is a model of the __single_pass_range__ Concept.
50* `BinaryPredicate` is a model of the `BinaryPredicateConcept`.
51* `SinglePassRange1`'s value type is convertible to `BinaryPredicate`'s first argument type.
52* `SinglePassRange2`'s value type is convertible to `BinaryPredicate`'s second argument type.
53
54[heading Complexity]
55
56Linear. At most `2 * min(distance(rng1), distance(rng2))` comparisons.
57
58[endsect]
59
60
61