43 lines
1.1 KiB
C++
43 lines
1.1 KiB
C++
//
|
|
// Created by light on 19-12-14.
|
|
//
|
|
|
|
#include <iostream>
|
|
#include <functional>
|
|
|
|
using namespace std;
|
|
|
|
// xvalue
|
|
int&& f(){
|
|
return 3;
|
|
}
|
|
|
|
struct As
|
|
{
|
|
int i;
|
|
};
|
|
|
|
As&& ff(){
|
|
return As();
|
|
}
|
|
|
|
int main() {
|
|
// lvalue
|
|
int x = 0;
|
|
cout << "(x).addr = " << &x << endl;
|
|
cout << "(x = 1).addr = " << &(x = 1) << endl;
|
|
cout << "(++x).addr = " << &++x << endl;
|
|
cout << "(cout << ' ').addr=" << &(cout << ' ') << endl;
|
|
cout << "(\"hello\").addr=" << &("hello") << endl;
|
|
// rvalue
|
|
cout<<true<<endl;
|
|
// xvalue
|
|
f(); // The expression f() belongs to the xvalue category, because f() return type is an rvalue reference to object type.
|
|
static_cast<int&&>(7); // The expression static_cast<int&&>(7) belongs to the xvalue category, because it is a cast to an rvalue reference to object type.
|
|
std::move(7); // std::move(7) is equivalent to static_cast<int&&>(7).
|
|
|
|
ff().i; // The expression f().i belongs to the xvalue category, because As::i is a non-static data member of non-reference type, and the subexpression f() belongs to the xvlaue category.
|
|
|
|
|
|
return 0;
|
|
} |