std::ranges..._view::begin(3)

💖 NAME 💖

std::ranges::drop_while_view::begin — okay bestie, this is the std::ranges..._view::begin(3) page from the C++ Standard Libary manual, and it’s literally the begin member of drop_while_view. No cap, it’s giving iterator-to-the-front energy. ✨

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✨ Synopsis ✨

constexpr auto begin();  (since C++20)

Returns an iterator to the first element of the view. 💅

Effectively returns ranges::find_if_not(base_, std::cref(pred())), where base_ is the underlying view. The behavior is undefined if *this does not store a predicate. 😭

⚠️ Warning bestie: undefined behavior if *this does not store a predicate. Not a vibe. Keep the predicate stored, fr fr.

In order to provide the amortized constant time complexity required by the range concept, this function caches the result within the drop_while_view object for use on subsequent calls. It’s lowkey doing main character caching so later calls stay fast. 🔥

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🌸 Parameters 🌸

(none) — literally zero parameters, bestie. Nothing. Nada. 🫶

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🎀 Return value 🎀

Iterator to the first element of the view. Periodt. 👑

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🦋 Example 🦋

Run this code, bestie 👇

#include <array>
#include <iostream>
#include <ranges>

int main()
{
    constexpr std::array data{ 0, -1, -2, 3, 1, 4, 1, 5 };

    auto view = std::ranges::drop_while_view{
        data, [](int x) { return x <= 0; }
    };

    std::cout << *view.begin() << '\n';
}

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🌈 Output 🌈

3

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👀 See also 👀

• end — returns an iterator or a sentinel to the end (C++20) (public member function) 💜

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Source/version: http://cppreference.com · date: 2024.06.10 — bye bestie, go slay those ranges 🧚💖🎀