list-swap

////////////////////////////////////////
//      2018/04/27 16:20:26
//      list-swap

// exchange two lists
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>

using namespace std;

void print(list<int> &l){
    list<int>::iterator it = l.begin();
    while (it != l.end()){
        cout << *(it++) << " ";
    }
    cout << endl;
}

//==========================

int main(){
    list<int> li1(5), li2(5);

    iota(li1.begin(), li1.end(), 1);
    iota(li2.begin(), li2.end(), 5);

    cout << "li1:";
    print(li1);
    cout << "li2:";
    print(li2);

    li1.swap(li2);

    cout << "After swapping:" << endl;
    cout << "li1:";
    print(li1);
    cout << "li2:";
    print(li2);

    return 0;
}

/*
OUTPUT:
    li1:1 2 3 4 5
    li2:5 6 7 8 9
    After swapping:
    li1:5 6 7 8 9
    li2:1 2 3 4 5
*/