In C++, what does & mean after a function's return type?

Question

In a C++ function like this:

int& getNumber();

what does the & mean? Is it different from:

int getNumb         


        

Answer 1

Yes, it's different.

The & means you return a reference. Otherwise it will return a copy (well, sometimes the compiler optimizes it, but that's not the problem here).

An example is vector. The operator[] returns an &. This allows us to do:

my_vector[2] = 42;

That wouldn't work with a copy.