deductionguidesforstd::array(3)

NAME
deductionguidesforstd::array - deductionguidesforstd::array

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