Fun C++ Problem

[whitevandal]

If n is -20, i=0 will never be less than n.
Interestingly, since I didn’t want to read past the first few posts, I did not realize that I played this game five years ago, and accidentally found (again) all three solutions. Again without timing; about 10 minutes, I guess.
Do I get a double bonus?

i is DEcremented, not INcremented. So i will= -1, -2, -3...etc until it passes -20.