What happened here...say int b=3; int a=16; b+=++a; system.out.println(b);

Question

how did the answer came to be....

Answer 1

b += ++a;
b += 4; // pre-increment
b = b + 4;
b = 20

Answer 2

@Mihail
The original value is not returned because this is the pre-increment (also called pre-fix)
++x first increments x then uses x.

So, b becomes 4, then 4 is returned.
16 + 4 = 20.

Answer 3

it should be 19
because ++a adds one but returns it's original value and 16+3=19