| .. Data Types/Miscellaneous//pair |10 |
| |
| pair |
| ==== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename T1 |
| , typename T2 |
| > |
| struct pair |
| { |
| typedef pair type; |
| typedef T1 first; |
| typedef T2 second; |
| }; |
| |
| |
| Description |
| ----------- |
| |
| A transparent holder for two arbitrary types. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/pair.hpp> |
| |
| |
| Example |
| ------- |
| |
| Count a number of elements in the sequence together with a number of negative |
| elements among these. |
| |
| .. parsed-literal:: |
| |
| typedef fold< |
| vector_c<int,-1,0,5,-7,-2,4,5,7> |
| , pair< int_<0>, int_<0> > |
| , pair< |
| next< first<_1> > |
| , if_< |
| less< _2, int_<0> > |
| , next< second<_1> > |
| , second<_1> |
| > |
| > |
| >::type p; |
| |
| BOOST_MPL_ASSERT_RELATION( p::first::value, ==, 8 ); |
| BOOST_MPL_ASSERT_RELATION( p::second::value, ==, 3 ); |
| |
| |
| See also |
| -------- |
| |
| |Data Types|, |Sequences|, |first|, |second| |
| |
| |
| .. 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) |
