std::unorde...t::max_size(3)

💅 NAME

std::unordered_set::max_size — literally what it says on the tin, bestie: the max size. That's the whole vibe. 🎀

Oh and just so we're clear, we're moving through the C++ Standard Libary today, mwah.

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✨ Synopsis

size_type max_size() const noexcept;  (since C++11)

Returns the maximum number of elements the container is able to hold due to system or library implementation limitations — i.e. std::distance(begin(), end()) for the largest container. That's the biggest one. The final boss container. 👑

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🌸 Parameters

None. Nada. Zero. Nothing to pass in — she works alone, main character energy fr fr. 💅

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💖 Return value

The maximum number of elements. That's it, that's the return. 🫶

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⚡ Complexity

Constant. Like, O(1) constant, no cap — she's not out here doing loops. Iconic behaviour honestly.

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🦋 Notes

Okay so this value typically reflects the theoretical limit on the size of the container — at most std::numeric_limits<difference_type>::max(). Key word: theoretical. 🙈

At runtime though, the size of the container may be limited to a value smaller than max_size() by the amount of RAM available. So like, your dreams may be bigger than your memory. Story of my life. 😭

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🍓 Example

// Run this code

#include <iostream>
#include <locale>
#include <unordered_set>

int main()
{
    std::unordered_set<char> p;
    std::unordered_set<long> q;

    std::cout.imbue(std::locale("en_US.UTF-8"));
    std::cout << std::uppercase
              << "p.max_size() = " << std::dec << p.max_size() << " = 0x"
              << std::hex << p.max_size() << '\n'
              << "q.max_size() = " << std::dec << q.max_size() << " = 0x"
              << std::hex << q.max_size() << '\n';
}

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🌈 Possible output

p.max_size() = 1,152,921,504,606,846,975 = 0xFFF,FFF,FFF,FFF,FFF
q.max_size() = 1,152,921,504,606,846,975 = 0xFFF,FFF,FFF,FFF,FFF

Look at those numbers. Comma-separated. Hex on the side. It's giving flex, honestly. 🔥

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👑 See also

• size — returns the number of elements (public member function)

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<div style="text-align:center">— 🧚 —</div>

Okay bestie that's the whole page! This came straight from http://cppreference.com and it's dated 2024.06.10, so if anything looks different later, don't come for me. Go forth and check your max_size(), you got this 💜✨