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#include <iostream>
using namespace std;
class Demo
{
public:
Demo() = default;
Demo(Demo const &other)
{
cout << "Copy constructor\n";
}
Demo(Demo &&tmp)
{
cout << "Move constructor\n";
}
Demo &operator+=(Demo const &rhs)
{
cout << "Copy +=\n";
Demo tmp(*this);
// add rhs to tmp
// swap tmp
cout << "copy += returns\n";
return *this;
}
};
Demo operator+(Demo &&lhs, Demo const &rhs)
{
cout << "move operator+\n";
lhs += rhs;
cout << "move operator+ returns\n";
return std::move(lhs);
}
Demo operator+(Demo const &lhs, Demo const &rhs)
{
cout << "copy operator+\n";
Demo tmp(lhs);
tmp += rhs;
cout << "copy operator+ returns\n";
return tmp;
}
int main()
{
Demo d1;
d1 + d1 + d1;
cout << "========\n";
Demo{} + d1 + d1;
}
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