std::ranges::min_max_result

Defined in header `<algorithm>`
template <class T> struct min_max_result;		(since C++20)

ranges::min_max_result is a class template that provides a way to store two objects or references of the same type as a single unit.

This class template has no base classes or declared members other than those shown below. Thus it is suitable for use with structured bindings.

All special member functions of this class template are implicitly declared, which makes specializations be aggregate classes, and propagate triviality, potentially-throwing-ness, and constexpr-ness of corresponding operations on data members.

std::ranges::min_max_result::min

[[no_unique_address]] T min;

May be a reference to, a copy of, or an iterator to a minimum element in a range.

std::ranges::min_max_result::max

[[no_unique_address]] T max;

May be a reference to, a copy of, or an iterator to a maximum element in a range.

[edit] Member functions

std::ranges::min_max_result::operator min_max_result<T2>

template<class T2> requires std::convertible_to<const T&, T2> constexpr operator min_max_result<T2>() const &;	(1)
template<class T2> requires std::convertible_to<T, T2> constexpr operator min_max_result<T2>() &&;	(2)

Converts *this to the result by constructing every data member of the result from the corresponding member of *this.

1) Equivalent to return {min, max};.

2) Equivalent to return {std::move(min), std::move(max)};.

[edit] Standard library

The following standard library functions use ranges::min_max_result as the return type:

Algorithm functions
ranges::minmax (C++20)	returns the smaller and larger of two elements (niebloid) [edit]
ranges::minmax_element (C++20)	returns the smallest and the largest elements in a range (niebloid) [edit]

[edit] Synopsis

namespace std::ranges {
    template<class T>
    struct min_max_result {
        [[no_unique_address]] T min;
        [[no_unique_address]] T max;
 
        template<class T2>
        requires std::convertible_to<const T&, T2>
        constexpr operator min_max_result<T2>() const & {
            return {min, max};
        }
 
        template<class T2>
        requires std::convertible_to<T, T2>
        constexpr operator min_max_result<T2>() && {
            return {std::move(min), std::move(max)};
        }
    };
}

[edit] Notes

Each standard library algorithm that uses this family of return types declares a new alias type, e.g. using merge_result = in_in_out_result<I1, I2, O>;.

The names for such aliases are formed by adding the suffix "_result" to the algorithm's name. So, the return type of std::ranges::merge can be named as std::ranges::merge_result.

Unlike std::pair and std::tuple, this class template has data members of meaningful names.

[edit] Example

Run this code

#include <algorithm>
#include <ranges>
 
int main()
{
    constexpr static auto v = {3, 1, 4, 1, 5, 9, 2};
    {
        constexpr auto result = std::ranges::minmax(v);
        static_assert(1 == result.min && 9 == result.max);
    }
    {
        constexpr auto result = std::ranges::minmax_element(v);
        static_assert(1 == *result.min && 9 == *result.max);
    }
}

[edit] See also

pair	implements binary tuple, i.e. a pair of values (class template) [edit]
tuple (C++11)	implements fixed size container, which holds elements of possibly different types (class template) [edit]

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Return types
in_fun_result (C++20)
in_in_result (C++20)
in_out_result (C++20)
in_in_out_result (C++20)
in_out_out_result (C++20)
min_max_result (C++20)
in_found_result (C++20)
in_value_result (C++23)
out_value_result (C++23)

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std::ranges::min_max_result

Contents

[edit] Template parameters

[edit] Data members