Variable below zero but if statement doesn't grab?

[SimonN via Digitalmars-d-learn]

On Sunday, 27 December 2015 at 16:41:10 UTC, TheDGuy wrote:
> It looks like the debugger is not working correctly because i 
> changed the code to this:
> [...]
> and the same problem appears.

I can't watch youtube here. What numbers does your input 
generate? Which 'if' doesn't fire? What results would you like 
instead?

-- Simon