deduction guides for std::array

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

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

Views

span (C++20)

 

std::array

Member functions

Element access

array::at

array::operator[]

array::front

array::back

array::data

Iterators

array::beginarray::cbegin

array::endarray::cend

array::rbeginarray::crbegin

array::rendarray::crend

Capacity

array::empty

array::size

array::max_size

Modifiers

array::fill

array::swap

Non-member functions

get

std::swap

to_array (C++20)

operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Helper classes

tuple_size

tuple_element

Deduction guides(C++17)

 

Defined in header <array>
template <class T, class... U> array(T, U...) -> array<T, 1 + sizeof...(U)>;		(since C++17)

One deduction guide is provided for std::array to provide an equivalent of std::experimental::make_array for construction of std::array from a variadic parameter pack.

The program is ill-formed if (std::is_same_v<T, U> && ...) is not true. Note that (std::is_same_v<T, U> && ...) is true when sizeof...(U) is zero.

Example

Run this code

#include <array>
#include <cassert>
 
int main()
{
    int const x = 10;
    std::array a{1, 2, 3, 5, x}; // OK, creates std::array<int, 5>
    assert(a.back() == x);
 
//  std::array b{1, 2u}; // Error, all arguments must have same type
 
//  std::array<short> c{3, 2, 1}; // Error, wrong number of template args
    std::array c(std::to_array<short>({3, 2, 1})); // C++20 alternative, creates std::array<short, 3>
}