Function that returns an string refrence c++

Question

im new to pointers and refrences in c++ so i was wondering if someone could show me an example of how to write a function that returns a string refrence and maybe the function being used. For example if i wanted to write a function like...

//returns a refrence to a string
string& returnRefrence(){


    string hello = "Hello there";
    string * helloRefrence = &hello;

    return *helloRefrence;
}

//and if i wanted to use to that function to see the value of helloRefrence would i do something like this?

string hello = returnRefrence();
cout << hello << endl;

Answer 1

A function such as

string& returnRefrence(){}

would only make sense in a context where is has access to a string that lives beyond it's own scope. This could be, for example, a member function of a class that has a string data member, or a function that has access to some global string object. A string created in the body of the function is destroyed on exiting that scope, so returning a reference to it results in a dangling reference.

Another option where is could make sense is if the function tkaes a string by reference, and returns a reference to that very string:

string& foo(string& s) {
  // do something with s
  return s;
}

Answer 2

You could also declare the variable as static:

std::string &MyFunction()
{
    static std::string hello = "Hello there";
    return hello;
}

However, note that the exact same string object will be return as reference on each call.

For instance,

std::string &Call1 = MyFunction();
Call1 += "123";

std::string Call2 = MyFunction(); //Call2 = "Hello there123", NOT "hello there"

The Call2 object is the same string referenced in Call1, so it returned its modified value