std::vector<bool,Allocator>::swap

 

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std::vector<bool>

Member types
vector<bool>::reference
Member functions
vector::vector vector::~vector vector::operator= vector::assign vector::assign_range (C++23) vector::get_allocator Element access vector::operator[] vector::at vector::front vector::back Iterators vector::beginvector::cbegin (C++11) vector::endvector::cend (C++11) vector::rbeginvector::crbegin (C++11) vector::rendvector::crend (C++11)	Capacity vector::empty vector::size vector::max_size vector::capacity vector::resize vector::reserve vector::shrink_to_fit (DR*) Modifiers vector::clear vector::erase vector::insert vector::insert_range (C++23) vector::append_range (C++23) vector::emplace (C++11) vector::emplace_back (C++11) vector::push_back vector::pop_back vector::swap vector<bool>::flip vector<bool>::swap
Non-member functions
operator==operator<=> (C++20) swap(std::vector<bool>) erase(std::vector<bool>)erase_if(std::vector<bool>) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Helper classes
hash<std::vector<bool>> (C++11)
Deduction guides (C++17)

 

Defined in header <vector>
static void swap( reference x, reference y );		(constexpr since C++20)

Swaps the contents of x and y as if by bool b = x; x = y; y = b;.

Parameters

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

Return value

(none)

Complexity

Constant.

Example

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

Defect reports

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

DR	Applied to	Behavior as published	Correct behavior
LWG 814	C++98	the description of this member function was missing	added

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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