111 lines
2.2 KiB
ReStructuredText
111 lines
2.2 KiB
ReStructuredText
.. Sequences/Intrinsic Metafunctions//push_back
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push_back
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=========
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Synopsis
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--------
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.. parsed-literal::
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template<
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typename Sequence
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, typename T
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>
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struct push_back
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{
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typedef |unspecified| type;
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};
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Description
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-----------
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``push_back`` performs an insertion at the end of the sequence with guaranteed |O(1)|
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complexity.
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Header
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------
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.. parsed-literal::
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#include <boost/mpl/push_back.hpp>
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Model of
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--------
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|Tag Dispatched Metafunction|
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Parameters
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----------
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+---------------+-------------------------------+-----------------------------------------------+
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| Parameter | Requirement | Description |
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+===============+===============================+===============================================+
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| ``Sequence`` | |Back Extensible Sequence| | A sequence to insert into. |
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+---------------+-------------------------------+-----------------------------------------------+
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| ``T`` | Any type | The element to be inserted. |
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+---------------+-------------------------------+-----------------------------------------------+
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Expression semantics
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--------------------
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For any |Back Extensible Sequence| ``s`` and arbitrary type ``x``:
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.. parsed-literal::
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typedef push_back<s,x>::type r;
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:Return type:
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|Back Extensible Sequence|.
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:Semantics:
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Equivalent to
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.. parsed-literal::
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typedef insert< s,end<s>::type,x >::type r;
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:Postcondition:
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``back<r>::type`` is identical to ``x``;
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.. parsed-literal::
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size<r>::value == size<s>::value + 1
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Complexity
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----------
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Amortized constant time.
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Example
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-------
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.. parsed-literal::
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typedef vector_c<bool,false,false,false,
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true,true,true,false,false> bools;
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typedef push_back<bools,false_>::type message;
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BOOST_MPL_ASSERT_RELATION( back<message>::type::value, ==, false );
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BOOST_MPL_ASSERT_RELATION(
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( count_if<message, equal_to<_1,false_> >::value ), ==, 6
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);
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See also
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--------
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|Back Extensible Sequence|, |insert|, |pop_back|, |back|, |push_front|
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