std::span::size(3)

👑 std::span::size 👑

okay so bestie, this is the <std::span::size>(3) page from the C++ Standard Libary — yes, that’s the spelling in the header, and we’re keeping it 💅. It’s giving “tiny member function, main character energy,” and we’re gonna get through every detail together, fr fr. ✨

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💖 NAME 💖

std::span::size — literally std::span::size. That’s the name, bestie. No plot twist, no secret second identity. 🎀

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🌸 Synopsis 🌸

Here’s the signature, and yes it’s constexpr, const noexcept, and since C++20 — the whole slay package 🔥:

constexpr size_type size() const noexcept;  (since C++20)

It returns the number of elements in the span. That’s the vibe. 🦋

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🎀 Parameters 🎀

(none) — not a single parameter, zero, nada, the void, and we respect it 🫶.

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💜 Return value 💜

It returns the number of elements in the span — that’s the whole return value, bestie 💖.

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⭐ Note ⭐

Feature-test macro tea ☕:

• Feature-test macro: __cpp_lib_ssize
  • Value: 201902L
  • Std: (C++20)
  • Feature: std::ssize and unsigned std::span::size

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🌈 Example 🌈

// Run this code

#include <iostream>
#include <span>

void show_sizes(std::span<const int> span)
{
    std::cout
        << span                 .size() << ' ' // 8
        << span.first(7)        .size() << ' ' // 7
        << span.first<6>()      .size() << ' ' // 6
        << span.last(5)         .size() << ' ' // 5
        << span.last<4>()       .size() << ' ' // 4
        << span.subspan(2, 3)   .size() << ' ' // 3
        << span.subspan<3, 2>() .size() << ' ' // 2
        << '\n';
}

int main()
{
    int antique_array[]{1, 2, 3, 4, 5, 6, 7, 8};
    show_sizes(antique_array);
}

Output:

8 7 6 5 4 3 2

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🦋 See also 🦋

• constructor — constructs a span (public member function) 🛠️
• size_bytes — returns the size of the sequence in bytes (public member function) 📏

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later bestie! this page is from http://cppreference.com, dated 2024.06.10, and the footer says std::span::size(3) — mwah 💋✨