decltype

#include <iostream>
using namespace std;

struct A
{
	double d;
	int i;
};

int main()
{
	int a = 3;
	decltype(a) b = 2;		//int

	int& r_a = a;
	decltype(r_a) r_b = b;	//int&

	int&& x = 3;
	decltype(x) y = 2;		//int&&

	A* aa;
	decltype(aa->d) dd = 0.1; // double

	 
}