C++创建引用

#include <iostream>

using namespace std;

int main () {
   // declare simple variables
   int    i;
   double d;

   // declare reference variables
   int&    r = i;
   double& s = d;

   i = 5;
   cout << Value of i :  << i << endl;
   cout << Value of i reference :  << r  << endl;

   d = 11.7;
   cout << Value of d :  << d << endl;
   cout << Value of d reference :  << s  << endl;

   return 0;
}