1.. Data Types/Miscellaneous//pair |10 2 3pair 4==== 5 6Synopsis 7-------- 8 9.. parsed-literal:: 10 11 template< 12 typename T1 13 , typename T2 14 > 15 struct pair 16 { 17 typedef pair type; 18 typedef T1 first; 19 typedef T2 second; 20 }; 21 22 23Description 24----------- 25 26A transparent holder for two arbitrary types. 27 28 29Header 30------ 31 32.. parsed-literal:: 33 34 #include <boost/mpl/pair.hpp> 35 36 37Example 38------- 39 40Count a number of elements in the sequence together with a number of negative 41elements among these. 42 43.. parsed-literal:: 44 45 typedef fold< 46 vector_c<int,-1,0,5,-7,-2,4,5,7> 47 , pair< int_<0>, int_<0> > 48 , pair< 49 next< first<_1> > 50 , if_< 51 less< _2, int_<0> > 52 , next< second<_1> > 53 , second<_1> 54 > 55 > 56 >::type p; 57 58 BOOST_MPL_ASSERT_RELATION( p::first::value, ==, 8 ); 59 BOOST_MPL_ASSERT_RELATION( p::second::value, ==, 3 ); 60 61 62See also 63-------- 64 65|Data Types|, |Sequences|, |first|, |second| 66 67 68.. copyright:: Copyright � 2001-2009 Aleksey Gurtovoy and David Abrahams 69 Distributed under the Boost Software License, Version 1.0. (See accompanying 70 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 71