A reference serves as an alternative name for an object.
Const reference is " reference to const ".
A const reference can be initialized to an object of adifferent type or to an rvalue , such as:
#include<iostream>
#include<string>
using namespace std;
int main()
{
double dval = 3.14;
const int &ri = dval;
cout << ri << endl << dval << endl;
}
the result is :
3
3.14
it won't change the value of dval