#include <string>

#include <iostream>

#include <utility>

#include <iomanip>

using namespace std;

struct A

{

string s;

int k;

A(): s("test"), k(-1) { }

A(const A& o): s(o.s), k(o.k) { cout << "move failed!\n"; }

A(A && o) noexcept :

s(move(o.s)),

k(exchange(o.k, 0))

{}

};

A f(A a)

{

return a;

}

struct B : A

{

string s2;

int n;

// implicit move constructur B::(B&&)

// calls A's move ctor

// calls s2's move constrctor

// and make a bitwise copy of n

};

struct C : B

{

~C() { } // destructor prevents implicit move ctor C::(C&&)

};

struct D : B

{

D() {}

~D() {} // destructor would prevent implicit move ctor D::(D&&)

D(D&&) = default; // forces a move ctor anyway

};

int main(int argc, char *argv[])

{

cout << "Trying to move A\n";

A a1 = f(A()); // return by value move-constructs the target from the function parameter

cout << "Befoer move, a1.s = " << quoted(a1.s) << " a1.k = " << a1.k << endl;

A a2 = move(a1); // move-constructs from xvalue

cout << " After move, a1.s = " << quoted(a1.s) << " a1.k = " << a1.k << endl;

cout << endl;

cout << "Trying to move B\n";

B b1;

cout << "Before move b1.s = " << quoted(b1.s) << endl;

B b2 = move(b1); // calls implicit move-ctor

cout << " After move, b1.s = " << quoted(b1.s) << endl;

cout << endl;

cout << "Trying to move C\n";

C c1;

C c2 = move(c1); // calls copy-ctor

cout << endl;

cout << "Trying to move D\n";

D d1;

cout << "Before move d1.s = " << quoted(d1.s) << endl;

D d2 = move(d1); // calls copy-ctor

cout << " After move, d1.s = " << quoted(d1.s) << endl;

cout << endl;

return 0;

}