#include <iostream>
#include <deque>
void printdq(std::deque <int> dq) {
for (auto &n: dq)
std::cout << n << ", ";
std::cout << '\n';
}
int main()
{
std::deque<int> dq1 = { 5, 2, 9, 12 };
std::deque<int> dq2 = { 7, 9, 13, 89 };
dq1.swap(dq2);
printdq(dq1);
printdq(dq2);
return 0;
}
/*
run:
7, 9, 13, 89,
5, 2, 9, 12,
*/