Holds the address of an object but behaves syntactically like an object.

  
type-id & cast-expression  

You can think of an lvalue reference as another name for an object. An lvalue reference declaration consists of an optional list of specifiers followed by a reference declarator. A reference must be initialized and cannot be changed.

Any object whose address can be converted to a given pointer type can also be converted to the similar reference type. For example, any object whose address can be converted to type char * can also be converted to type char &.

Do not confuse reference declarations with use of the address-of operator. When the &identifier is preceded by a type, such as int or char, identifier is declared as a reference to the type. When &identifier is not preceded by a type, the usage is that of the address-of operator.

The following example demonstrates the reference declarator by declaring a Person object and a reference to that object. Because rFriend is a reference to myFriend, updating either variable changes the same object.

// reference_declarator.cpp  
// compile with: /EHsc  
// Demonstrates the reference declarator.  
#include <iostream>  
using namespace std;  
  
struct Person  
{  
    char* Name;  
    short Age;  
};  
  
int main()  
{  
   // Declare a Person object.  
   Person myFriend;  
  
   // Declare a reference to the Person object.  
   Person& rFriend = myFriend;  
  
   // Set the fields of the Person object.  
   // Updating either variable changes the same object.  
   myFriend.Name = "Bill";  
   rFriend.Age = 40;  
  
   // Print the fields of the Person object to the console.  
   cout << rFriend.Name << " is " << myFriend.Age << endl;  
}  

Bill is 40  

References
Reference-Type Function Arguments
Reference-Type Function Returns
References to Pointers