How compiler understands prefix and postfix increment ?

Question

If n++ means n = n+1

Then ++n means ______?

Give expression

Answer 1

b=a++; // equal b=а; a=a+1;
b=++a; // equal а=а+1; b=а;

Answer 2

It's good answer according to the assignment increment Operation.

But what about simply:
n++
++n