projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | .. Sequences/Intrinsic Metafunctions//back |
| 2 | ||
| 3 | back | |
| 4 | ==== | |
| 5 | ||
| 6 | Synopsis | |
| 7 | -------- | |
| 8 | ||
| 9 | .. parsed-literal:: | |
| 10 | ||
| 11 | template< | |
| 12 | typename Sequence | |
| 13 | > | |
| 14 | struct back | |
| 15 | { | |
| 16 | typedef |unspecified| type; | |
| 17 | }; | |
| 18 | ||
| 19 | ||
| 20 | ||
| 21 | Description | |
| 22 | ----------- | |
| 23 | ||
| 24 | Returns the last element in the sequence. | |
| 25 | ||
| 26 | ||
| 27 | Header | |
| 28 | ------ | |
| 29 | ||
| 30 | .. parsed-literal:: | |
| 31 | ||
| 32 | #include <boost/mpl/back.hpp> | |
| 33 | ||
| 34 | ||
| 35 | Model of | |
| 36 | -------- | |
| 37 | ||
| 38 | |Tag Dispatched Metafunction| | |
| 39 | ||
| 40 | ||
| 41 | Parameters | |
| 42 | ---------- | |
| 43 | ||
| 44 | +---------------+---------------------------+-----------------------------------+ | |
| 45 | | Parameter | Requirement | Description | | |
| 46 | +===============+===========================+===================================+ | |
| 47 | | ``Sequence`` | |Bidirectional Sequence| | A sequence to be examined. | | |
| 48 | +---------------+---------------------------+-----------------------------------+ | |
| 49 | ||
| 50 | ||
| 51 | Expression semantics | |
| 52 | -------------------- | |
| 53 | ||
| 54 | For any |Bidirectional Sequence| ``s``: | |
| 55 | ||
| 56 | .. parsed-literal:: | |
| 57 | ||
| 58 | typedef back<s>::type t; | |
| 59 | ||
| 60 | :Return type: | |
| 61 | A type. | |
| 62 | ||
| 63 | :Precondition: | |
| 64 | ``empty<s>::value == false``. | |
| 65 | ||
| 66 | :Semantics: | |
| 67 | Equivalent to | |
| 68 | ||
| 69 | .. parsed-literal:: | |
| 70 | ||
| 71 | typedef deref< prior< end<s>::type >::type >::type t; | |
| 72 | ||
| 73 | ||
| 74 | ||
| 75 | Complexity | |
| 76 | ---------- | |
| 77 | ||
| 78 | Amortized constant time. | |
| 79 | ||
| 80 | ||
| 81 | Example | |
| 82 | ------- | |
| 83 | ||
| 84 | .. parsed-literal:: | |
| 85 | ||
| 86 | typedef range_c<int,0,1> range1; | |
| 87 | typedef range_c<int,0,10> range2; | |
| 88 | typedef range_c<int,-10,0> range3; | |
| 89 | ||
| 90 | BOOST_MPL_ASSERT_RELATION( back<range1>::value, ==, 0 ); | |
| 91 | BOOST_MPL_ASSERT_RELATION( back<range2>::value, ==, 9 ); | |
| 92 | BOOST_MPL_ASSERT_RELATION( back<range3>::value, ==, -1 ); | |
| 93 | ||
| 94 | ||
| 95 | See also | |
| 96 | -------- | |
| 97 | ||
| 98 | |Bidirectional Sequence|, |front|, |push_back|, |end|, |deref|, |at| | |
| 99 | ||
| 100 | ||
| 101 |