.. Algorithms/Querying Algorithms//contains |30.. Copyright Aleksey Gurtovoy, David Abrahams 2007... 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)contains========Synopsis--------.. parsed-literal::        template<          typename Sequence        , typename T        >    struct contains    {        typedef |unspecified| type;    };Description-----------Returns a true-valued |Integral Constant| if one or more elements in ``Sequence`` are identical to ``T``. Header------.. parsed-literal::        #include <boost/mpl/contains.hpp>Parameters----------+---------------+---------------------------+-----------------------------------+| Parameter     | Requirement               | Description                       |+===============+===========================+===================================+| ``Sequence``  | |Forward Sequence|        | A sequence to be examined.        |+---------------+---------------------------+-----------------------------------+| ``T``         | Any type                  | A type to search for.             |+---------------+---------------------------+-----------------------------------+Expression semantics--------------------For any |Forward Sequence| ``s`` and arbitrary type ``t``:.. parsed-literal::    typedef contains<s,t>::type r;:Return type:    |Integral Constant|.:Semantics:    Equivalent to    .. parsed-literal::                typedef not_< is_same<               find<s,t>::type            , end<s>::type            > >::type r;Complexity----------Linear. At most ``size<s>::value`` comparisons for identity. Example-------.. parsed-literal::        typedef vector<char,int,unsigned,long,unsigned long> types;    BOOST_MPL_ASSERT_NOT(( contains<types,bool> ));See also--------|Querying Algorithms|, |find|, |find_if|, |count|, |lower_bound|