what's the meaning of *&

Question

I am a java coder and not familar with the c++ language. But right now,i read the following code:

void method(A* a,A*& b);

A *a;
A *b;
method(a,b);
<         


        

Answer 1

Read it from right to left. A*& b says that b is a reference to an object that points to an A. Why is this useful? It allows you to directly modify the pointer that is being passed into the function. Whatever happens to b inside that function will be visible when the function returns.

Answer 2

b is a reference to a pointer of A.

So if method sets b, the b in scope of the call will be changed.