std::flat_map::end,(3)

okay bestie, welcome to std::flat_map::end,(3) from the C++ Standard Libary manual 💅✨ this is the group-chat recap, but every tiny detail is staying, fr fr.

🎀 NAME 🎀

std::flat_map::end, — literally std::flat_map::end, 🫶

🌸 Synopsis 🌸

three overloads, all since C++23, all noexcept — write these down exactly:

iterator end() noexcept;              (1) (since C++23)
const_iterator end() const noexcept;  (2) (since C++23)
const_iterator cend() const noexcept; (3) (since C++23)

Returns an iterator to the element following the last element of the flat_map.

This element acts as a placeholder; attempting to access it results in undefined behavior.

🚨 bestie, hear me: it is undefined behavior to try to access that placeholder element. do not touch it. not even a little. 😭

there's also a diagram situation named range-begin-end.svg — iconic little visual, no cap 🦋

✨ Parameters ✨

(none) — nada, zero, zilch 💀

💖 Return value 💖

Iterator to the element following the last element. that's the whole return value, periodt 🫶

🔥 Complexity 🔥

Constant. that's it. no extra lore. 🌈

🍓 Example 🍓

       // Run this code

        #include <iostream>
        #include <flat_map>

        int main()
        {
            std::flat_map<int, double> map{{4, 4.13}, {9, 9.24}, {1, 1.09}};

            for (auto it = map.cbegin(); it != map.cend(); ++it)
                std::cout << '[' << it->first << "] = " << it->second << '\n';

            // Unlike std::map's bidirectional iterators, the std::flat_map
       iterators
            // are random-access, so they can be used with the operator[]:
            auto it = map.cbegin();
            assert(it[0] == map[1]);
            assert(it[1] == map[4]);
            assert(it[2] == map[9]);
        }

👑 Output 👑

[1] = 1.09
[4] = 4.13
[9] = 9.24

🧚 See also 🧚

the see-also squad, in the original order:

• begin — returns an iterator to the beginning
• cbegin — (public member function)
• end
• cend — returns an iterator to the end of a container or array
• (C++11) — (function template)
• (C++14)

source/version: http://cppreference.com; date: 2024.06.10; page: std::flat_map::end,(3) — mwah, byeee 💖🎀