Confused about a bit of code.

http://pastebin.org/121306

Could a friendly soul explain to me why removing/changing the for-loop at line 68-69 changes the whole program?
It changes output from   1 2 3 4 5   to   3 2 1 5 4 
if the input is 5 4 3 2 1

I'm not a friendly soul, but what the hell. Lines 61-62.