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
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
| Front Page / Sequences / Intrinsic Metafunctions / push_front |
template<
typename Sequence
, typename T
>
struct push_front
{
typedef unspecified type;
};
push_front performs an insertion at the beginning of the sequence with guaranteed O(1) complexity.
#include <boost/mpl/push_front.hpp>
| Parameter | Requirement | Description |
|---|---|---|
| Sequence | Front Extensible Sequence | A sequence to insert into. |
| T | Any type | The element to be inserted. |
For any Front Extensible Sequence s and arbitrary type x:
typedef push_front<s,x>::type r;
| Return type: | |
|---|---|
| Semantics: | Equivalent to typedef insert< s,begin<s>::type,x >::type r; |
| Postcondition: | size<r>::value == size<s>::value + 1; front<r>::type is identical to x. |
Amortized constant time.
typedef vector_c<int,1,2,3,5,8,13,21> v; BOOST_MPL_ASSERT_RELATION( size<v>::value, ==, 7 ); typedef push_front< v,integral_c<int,1> >::type fibonacci; BOOST_MPL_ASSERT_RELATION( size<fibonacci>::value, ==, 8 ); BOOST_MPL_ASSERT(( equal< fibonacci , vector_c<int,1,1,2,3,5,8,13,21> , equal_to<_,_> > ));