std::basic_...iew::rbegin,(3)

💅 NAME

okay so bestie, this is std::basic_string_view::rbegin — yes the page title is literally std::basic_...iew::rbegin,(3) because the C++ Standard Library manpage is out here doing the absolute most with abbreviations 😭 — and it's about getting a reverse iterator pointed at the first character of the reversed view ✨

(also yes, this lives in the C++ Standard Library, in case the parenthetical vibe check wasn't clear 🫶)

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✨ Synopsis

Two overloads, both of them besties since C++17:

constexpr const_reverse_iterator rbegin() const noexcept;   (since C++17)
constexpr const_reverse_iterator crbegin() const noexcept;  (since C++17)

So what are these actually doing? They return a reverse iterator to the first character of the reversed view 🔥 And that corresponds to the last character of the non-reversed view. Not me explaining it in two directions but like — that's genuinely what it is 💀

There's also a lil diagram on the page, range-rbegin-rend.svg, if you're a visual learner 🎀

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🌸 Parameters

(none)

Literally zero arguments. She takes nothing. Iconic, low-effort, no notes 👑

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🦋 Return value

A const_reverse_iterator to the first character. That's it, that's the whole deal 💖

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⭐ Complexity

Constant. Constannnttt. O(1) behavior, main character energy, in and out, no drama 🌈

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🌺 Example

Run this code, fr fr:

// Run this code

#include <algorithm>
#include <iostream>
#include <iterator>
#include <string_view>

int main()
{
    std::ostream_iterator<char> out_it(std::cout);
    std::string_view str_view("abcdef");

    std::copy(str_view.rbegin(), std::next(str_view.rbegin(), 3), out_it);
    *out_it = '\n';

    std::copy(str_view.crbegin(), std::next(str_view.crbegin(), 3), out_it);
    *out_it = '\n';
}

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💜 Output

fed
fed

fed twice — rbegin() ate and left no crumbs, then crbegin() came through and did the exact same thing 🍓 (the string is "abcdef", so reversed you're reading it backwards from the f, hence fed — iykyk 😌)

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🧚 See also

• rend — returns a reverse iterator to the end
• crend — (public member function)
• rbegin — returns a reverse iterator to the beginning
• crbegin — (public member function of std::basic_string<CharT,Traits,Allocator>) (C++11)

like yes, they're the sibling functions, and yes one of them is from std::basic_string not the view, that's just how the page lists it, don't come for me 🙈

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ngl the docs are honest about nothing here being dangerous — no UB, no deprecation, no gotchas, everything's constexpr and noexcept and safe. Slay. 💅

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and that's the page!! brought to you by cppreference.com 💖 version/date stamp 2024.06.10, and the original footer named it std::basic_...iew::rbegin,(3) — so go forth, reverse-iterate responsibly, and remember: last character of the normal view = first character of the reversed view, periodt 🎀✨