Done, thanks for pointing this out!

You're absolutely right, thanks for spotting this. I think I've fixed the issue.
Clever how you beat the static tests as well as the random ones!

What do you mean?

I had the same issue and it was because my index had exceeded the bounds of the string str, so blank characters were being added to my result. Maybe have another look at your loop conditions? Try printing the string one char at a time to see where the blanks are being added

This is really helpful to know, and something I hadn't thought about. Thanks

My mistake! Sorry about that. Thanks for letting me know