​In addition to passing values to a function by reference, C++ also has the ability to return a value by reference.

# Code

Consider the code snippet below where the function returns a value by reference: 

#include <iostream>
using namespace std;

// Global variable
string str;

// Note how the function is declared. It returns the
// address of a string (str).
string& test() 
{
  return str;
};

int main()
{
    test() = "The quick brown fox.";
    cout << str;
    return 0;
}

## Explanation

- The return type of the function `test` is `string&`. This makes it return a *reference* to the variable `str` instead of the variable itself.
- Note how the function call is used on the left side of the assignment statement on *line 16*. Since the *address* of `str` is returned, it can be assigned a value.
- This stores "The quick brown fox" into the global variable `str`.

> Note that local variables cannot be returned from a function that is defined to return values by reference. 

How to return a value by reference in C++

Returning by reference in C++ allows functions to modify global variables but not local ones.