deduction guides for std::deque

 

C++

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Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

span (C++20)

 

std::deque

Member functions

deque::deque

deque::~deque

deque::operator=

deque::assign

deque::get_allocator

Element access

deque::front

deque::back

Iterators

deque::begindeque::cbegin (C++11)

deque::enddeque::cend (C++11)

deque::rbegindeque::crbegin (C++11)

deque::renddeque::crend (C++11)

Capacity

deque::empty

deque::size

deque::max_size

deque::shrink_to_fit

Modifiers

deque::clear

deque::insert

deque::emplace

deque::erase

deque::push_front

deque::emplace_front

deque::pop_front

deque::push_back

deque::emplace_back

deque::pop_back

deque::resize

deque::swap

Deduction guides(C++17)

 

Defined in header <deque>
template< class InputIt,           class Alloc = std::allocator<typename std::iterator_traits<InputIt>::value_type>> deque(InputIt, InputIt, Alloc = Alloc())   -> deque<typename std::iterator_traits<InputIt>::value_type, Alloc>;		(since C++17)

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

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.

Example

Run this code

#include <deque>
#include <vector>
int main() {
   std::vector<int> v = {1, 2, 3, 4};
 
   // uses explicit deduction guide to deduce std::deque<int>
   std::deque x(v.begin(), v.end()); 
 
   // deduces std::deque<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::deque y{v.begin(), v.end()}; 
}