.. Algorithms/Querying Algorithms//equal |100

equal

Synopsis

.. parsed-literal::

template<
      typename Seq1
    , typename Seq2
    , typename Pred = is_same<_1,_2>
    >
struct equal
{
    typedef |unspecified| type;
};

Description

Returns a true-valued |Integral Constant| if the two sequences Seq1 and Seq2 are identical when compared element-by-element.

Header

.. parsed-literal::

#include <boost/mpl/equal.hpp>

Parameters

+-------------------+-------------------------------+-----------------------------------+ | Parameter | Requirement | Description | +===================+===============================+===================================+ | Seq1, Seq2| |Forward Sequence| | Sequences to compare. | +-------------------+-------------------------------+-----------------------------------+ | Pred | Binary |Lambda Expression| | A comparison criterion. | +-------------------+-------------------------------+-----------------------------------+

Expression semantics

For any |Forward Sequence|\ s s1 and s2 and a binary |Lambda Expression| pred:

.. parsed-literal::

typedef equal<s1,s2,pred>::type c; 

:Return type: |Integral Constant|

:Semantics: c::value == true is and only if size<s1>::value == size<s2>::value and for every iterator i in |begin/end<s1>| deref<i>::type is identical to

.. parsed-literal::

    advance< begin<s2>::type, distance< begin<s1>::type,i >::type >::type

Complexity

Linear. At most size<s1>::value comparisons.

Example

.. parsed-literal::

typedef vector<char,int,unsigned,long,unsigned long> s1;
typedef list<char,int,unsigned,long,unsigned long> s2;

BOOST_MPL_ASSERT(( equal<s1,s2> ));

See also

|Querying Algorithms|, |find|, |find_if|

.. copyright:: Copyright 2001-2009 Aleksey Gurtovoy and David Abrahams 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)