std::unordered_map::empty(3)

🌸 NAME 🌸

okay bestie, this is the manual page for std::unordered_map::empty from the C++ Standard Libary — yes, that's the manual name, spelling and all, and it's manual section 3 💅. The NAME line is literally std::unordered_map::empty - std::unordered_map::empty, which is giving "I said what I said" energy, and honestly? iconic.

✨ 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 vibe check: is the map empty or not? 👑

🎀 Parameters 🎀

(none) — she takes zero parameters. no notes. 💅

🌈 Return value 🌈

true if the container is empty, false otherwise. simple as that, bestie 🫶

🔥 Complexity 🔥

Constant. that's it. constant. no cap.

🍓 Example 🍓

The following code uses empty to check if a std::unordered_map<int, int> contains any elements:

// Run this code

#include <iostream>
#include <unordered_map>
#include <utility>

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

    numbers.emplace(42, 13);
    numbers.insert(std::make_pair(13317, 123));
    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 (C++17) — checks whether the container is empty (function template)

xoxo, sourced from http://cppreference.com, version/date 2024.06.10, on the std::unordered_map::empty(3) page 💖✨ now go forth and check your containers, bestie 🫶