Hi, Could You explpain me, why $res=6 in the END is the result of the code below?

Question

https://code.sololearn.com/wYdY3oY85zjC/?ref=app

Answer 1

a start with 3
that means for each push
r[0]=3
r[1]=4
r[2]=5
r[3]=6

Answer 2

Thank You, Teste. That'sright

Answer 3

Thanks You too, Prokopios!!!

Answer 4

Loop Iteration
-- ===========
1 : $i = 3 ; $res[0] = 3
2 : $i = 4 ; $res[1] = 4
3 : $i = 5 ; $res[2] = 5
4 : $i = 6 ; $res[3] = 6
5 : $i = 7 ; $res[4] = 7
6 : $i = 8 ; $res[5] = 8
7 : $i = 9 ; $res[6] = 9

As a result, $res[3] = 6