W3cubDocs

/C++

deduction guides for std::valarray

Defined in header <valarray> 
template<typename T, std::size_t cnt>
valarray(const T(&)[cnt], std::size_t) -> valarray<T>;
 (since C++17)

This deduction guide is provided for std::valarray to allow deduction from array and size (note that deduction from pointer and size is covered by the implicit guides).

Example

#include <valarray>
#include <iostream>
 
int main()
{
    int a[] = {1, 2, 3, 4};
    std::valarray va(a, 3); // uses explicit deduction guide
    for (int x : va)
        std::cout << x << ' ';
}

Output:

1 2 3

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/numeric/valarray/deduction_guides