What does '&' mean in C++?

Question

What does \'&\' mean in C++?

As within the function

void Read_wav::read_wav(const string &filename)
{

}

And what is its equiv

Answer 1

It means that the variable is a reference. There is no direct equivalent in C. You can think of it as a pointer that is automatically dereferenced when used, and can never be NULL, maybe.

The typical way to represent a string in C is by a char pointer, so the function would likely look like this:

void read_wav(struct Read_wav* instance, const char *filename)
{
}

Note: the first argument here simulates the implicit this object reference you would have in C++, since this looks like a member method.