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std::optional<T>::end - cppreference.com

From cppreference.com

constexpr iterator end() noexcept;

 (since C++26)

constexpr const_iterator end() const noexcept;

 (since C++26)

Returns a past-the-end iterator. Equivalent to return begin() + has_value();.

Return value

Past-the-end iterator

Complexity

Constant.

Notes

Feature-test macro Value Std Feature
__cpp_lib_optional_range_support 202406L (C++26) Range support for std::optional

Example

#include <optional>
#include <print>

int main()
{
    constexpr std::optional<int> none{std::nullopt}; // optional @1
    constexpr std::optional<int> some{42};           // optional @2

    static_assert(none.begin() == none.end());
    static_assert(some.begin() != some.end());

    // ranged-for loop support
    for (int i : none)
        std::println("Optional @1 has a value of {}", i);

    for (int i : some)
        std::println("Optional @2 has a value of {}", i);
}

Output: 

Optional @2 has a value of 42

See also

returns an iterator to the beginning
(public member function) [edit]