#include <iostream>#include <vector> void println(std::string_view fmt,std::vector<bool>const& vb={}){for(std::cout<< fmt;boolconst 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);}

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