please explain

Question

What is the output of the following code?
int a=3;
int b=2;
b=a++;
cout<<++b;

the answer was 4 but why, a plus 1 is 4 if b=4 plus 1 its 5 its 4 just if you don't add the last line ++b

Answer 1

a = 3

b = a++ //b takes the value 3 because you're using a postfix ++, postfix first return value 3 then increment it to 4

cout << ++b // now you're using prefix, first increment the value b = 3, then return it, b=4

Answer 2

https://www.sololearn.com/Discuss/1690694/?ref=app