Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an old version of boost. Click here for the latest version's documentation home page.

[Home]not_equal_to

Synopsis

template<
      typename T1
    , typename T2
    >
struct not_equal_to
{
    typedef unspecified type;
};

Description

Returns true_ if T1::value != T2::value and false_ otherwise [1].

Definition

#include "boost/mpl/not_equal_to.hpp"

Parameters

 Parameter  Requirement  Description  
T1, T2A model of Integral Constant

Expression semantics

 Expression  Expression type  Precondition  Semantics  Postcondition 
typedef not_equal_to<t1,t2>::type c;A model of bool Integral ConstantEquivalent to typedef bool_<(t1::value != t2::value)> c;

Complexity

Amortized constant time.

Example

typedef list_c<int,1,5,0,7,5,-1,2,4,5> numbers;
typedef remove_if< numbers, not_equal_to<_1,int_<5> > >::type fives;
BOOST_STATIC_ASSERT(equal_to< count_if< fives, equal_to<_1,int_<5> > >::type, size<fives>::type >::type::value));

Notes

[1] The not_equal_to metafunction can be (and is expected to be) specialized by user to work on user-defined types that do not satisfy the Integral Constant requirements. The requirements listed here are the ones imposed by the default implementation.

See also

Metafunctions, equal_to, less, less_equal, greater, greater_equal


Table of Contents
Last edited March 10, 2003 6:20 am