13.6 重载引用函数

Foo class:

#include <vector>
#include <algorithm>

using namespace std;

class Foo {
public:
    Foo() { std::cout << "default construct" << std::endl;}
    Foo(const Foo &f) : data(f.data) {std::cout << "copy construct" << std::endl;}
    Foo sort() &&;
    Foo sort() const &;
private:
    vector<int> data;
};

Foo Foo::sort() && {
    std::cout << "rvalue sort" << std::endl;
    std::sort(data.begin(), data.end());
    return *this;
}

Foo Foo::sort() const & {
    std::cout << "lvalue sort" << std::endl;
    return Foo(*this).sort();
}

main.cpp

#include <iostream>
#include <string>
#include "Foo.h"

using namespace std;

int main() {
    Foo f;
    f.sort();
}

result:

default construct
lvalue sort
copy construct
rvalue sort
copy construct