std::unordered_set::empty(3)

✨ NAME ✨

okay bestie, meet std::unordered_set::empty(3) — the manual page that is literally named std::unordered_set::empty — fresh from the C++ Standard Libary (yes, that’s their spelling, not mine 💅). This is your group-chat explainer for checking whether a std::unordered_set is empty. No cap.

🎀 Synopsis 🎀

bool empty() const noexcept;                (since C++11)
                                            (until C++20)
[[nodiscard]] bool empty() const noexcept;  (since C++20)

it checks if the container has no elements, i.e. whether begin() == end(). That’s the whole litmus test, bestie. 🦋

🌸 Parameters 🌸

(none) — literally zero parameters. not a single one. she takes no arguments and serves. 💅

💖 Return value 💖

true if the container is empty, false otherwise. periodt. ✨

🔥 Complexity 🔥

Constant. that’s it. constant. no scrolling required. 👑

🧚 Example 🧚

The following code uses empty to check if a std::unordered_set<int> contains any elements. There’s a // Run this code moment in the original, and then this exact code:

        #include <iostream>
        #include <unordered_set>

        int main()
        {
            std::unordered_set<int> numbers;
            std::cout << std::boolalpha;
            std::cout << "Initially, numbers.empty(): " << numbers.empty() <<
       '\n';

            numbers.insert(42);
            numbers.insert(19937);
            std::cout << "After adding elements, numbers.empty(): " <<
       numbers.empty() << '\n';
        }

🦋 Output: 🦋

Initially, numbers.empty(): true
After adding elements, numbers.empty(): false

👑 See also 👑

• size — returns the number of elements (public member function)
• empty — checks whether the container is empty (C++17) (function template)

and that’s the tea 🍓 — source: http://cppreference.com, version/date: 2024.06.10, page: std::unordered_set::empty(3). mwah 💋