std::vector::swap(3)

💖 NAME 💖

okay bestie, welcome to the std::vector::swap(3) page from the C++ Standard Libary manual — yes, that’s the manual name, and we’re keeping it exactly as it appears ✨

The name is literally:

std::vector::swap - std::vector::swap

that’s it, that’s the NAME section, no cap 💅

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✨ Synopsis ✨

Defined in header <vector> 🎀

static void swap( reference x, reference y );            (until C++20)
constexpr static void swap( reference x, reference y );  (since C++20)

Swaps the contents of x and y as if by bool b = x; x = y; y = b;. fr fr, that’s the exact stated recipe 🔥

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🎀 Parameters 🎀

• x — std::vector<bool>::reference value to swap with y
• y — std::vector<bool>::reference value to swap with x

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🫶 Return value 🫶

(none) — literally no return value, bestie 😭

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⚡ Complexity ⚡

Constant. — constant, periodt 💅

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🌈 Example 🌈

Run this code, bestie:

// Run this code

#include <iostream>
#include <vector>

void println(std::string_view fmt, std::vector<bool> const& vb = {})
{
    for (std::cout << fmt; bool const e : vb)
        std::cout << e << ' ';
    std::cout << '\n';
}

int main()
{
    println("swap elements of the same vector:");
    std::vector<bool> x{1, 0};
    println("before swap, x: ", x);
    x.swap(x[0], x[1]); // same as std::vector<bool>::swap(x[0], x[1]);
    println("after swap,  x: ", x);

    println("swap elements of two different vectors:");
    std::vector<bool> y{0, 0, 1};
    println("before swap, x: ", x);
    println("before swap, y: ", y);
    y.swap(x[0], y[2]); // same as std::vector<bool>::swap(x[0], y[2]);
    println("after swap,  x: ", x);
    println("after swap,  y: ", y);
}

💅 Output 💅

swap elements of the same vector:
before swap, x: 1 0
after swap,  x: 0 1
swap elements of two different vectors:
before swap, x: 0 1
before swap, y: 0 0 1
after swap,  x: 1 1
after swap,  y: 0 0 0

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🧚 Defect reports 🧚

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

• LWG 814 — applied to C++98; behavior as published: the description of this member function was missing; correct behavior: added.

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👑 See also 👑

• reference — proxy class representing a reference to a single bool (class)
• swap — swaps the contents (public member function of std::vector<T,Allocator>)
• std::swap(std::vector) — specializes the std::swap algorithm (function template)

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xoxo, your std::vector::swap(3) bestie — source/version http://cppreference.com, dated 2024.06.10 💖