let suppose $int$ $a = 5$ and size of int is $4B$ and add of a is 1000 then
$a+1$ then it will be $6$.
$&a+1 $ means address of $a$ + size of $a$ $= 1000+4 = 1004$
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Come to Question , here $s$ is an array and size of $s$ is $6B$.
$&s+1$ $= 1000+6$
$int$ $*str = $$(int $ $*)1006$ //Array pointer is typecasted to integer pointer.
Now $str$ contain 1006.
It will print $1006$.
let me know if i missed something.