deduction guides for std::vector

 

C++

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

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Diagnostics library

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Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

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Filesystem library (C++17)

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Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

Views

span (C++20)

mdspan (C++23)

Tables

Iterator invalidation

Member function table

Non-member function table

 

std::vector

Member types
Member functions
vector::vector vector::~vector vector::operator= vector::assign vector::assign_range (C++23)   vector::get_allocator Element access vector::operator[] vector::at vector::data vector::front vector::back Iterators vector::beginvector::cbegin (C++11) vector::endvector::cend (C++11) vector::rbeginvector::crbegin (C++11) vector::rendvector::crend (C++11)	Capacity vector::empty vector::size vector::max_size vector::reserve vector::capacity vector::shrink_to_fit (DR*) Modifiers vector::clear vector::erase vector::insert vector::insert_range (C++23) vector::append_range (C++23) vector::emplace (C++11) vector::emplace_back (C++11) vector::push_back vector::pop_back vector::resize vector::swap
Non-member functions
operator==operator<=> (C++20) swap(std::vector) erase(std::vector)erase_if(std::vector) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides(C++17)

 

Defined in header <vector>
template< class InputIt,           class Alloc = std::allocator<               typename std::iterator_traits<InputIt>::value_type> > vector( InputIt, InputIt, Alloc = Alloc() )     -> vector<typename std::iterator_traits<InputIt>::value_type, Alloc>;	(1)	(since C++17)
template< ranges::input_range R,           class Alloc = std::allocator<ranges::range_value_t<R>> > vector( std::from_range_t, R&&, Alloc = Alloc() )     -> vector<ranges::range_value_t<R>, Alloc>;	(2)	(since C++23)

1) This deduction guide is provided for vector to allow deduction from an iterator range. This overload participates in overload resolution only if InputIt satisfies LegacyInputIterator and Alloc satisfies Allocator.

2) This deduction guide is provided for vector to allow deduction from a std::from_range_t tag and an input_range.

Note: the extent to which the library determines that a type does not satisfy LegacyInputIterator is unspecified, except that as a minimum integral types do not qualify as input iterators. Likewise, the extent to which it determines that a type does not satisfy Allocator is unspecified, except that as a minimum the member type Alloc::value_type must exist and the expression std::declval<Alloc&>().allocate(std::size_t{}) must be well-formed when treated as an unevaluated operand.

Notes

Feature-test macro	Value	Std	Feature
__cpp_lib_containers_ranges	202202L	(C++23)	Ranges-aware construction and insertion; overload (2)

Example

Run this code

#include <vector>
 
int main()
{
    std::vector<int> v = {1, 2, 3, 4};
 
    // uses explicit deduction guide to deduce std::vector<int>
    std::vector x(v.begin(), v.end());
 
    // deduces std::vector<std::vector<int>::iterator>
    // first phase of overload resolution for list-initialization selects the candidate
    // synthesized from the initializer-list constructor; second phase is not performed
    // and deduction guide has no effect
    std::vector y{v.begin(), v.end()};
}