This makes me want to weep

Another minor optimization for anyone else who might be viewing; you can start the loop from 1 rather than 0, since you already grabbed the first char of the full_name string

Wondering if it has something to do with the number being at the start of the word, but that doesn't quite make sense

But that's exactly it ;-) %[] only matches a non-empty sequence of characters. As soon as the match fails, sscanf() returns, without parsing the integer.

You wrong, because string VOWELS is of constant length (5) and does not depend on an input. So it will be O(n*const) = O(n).

jeff

i'm deceased

This code doesn't follow typical styling, which would have the line broken into a couple new lines and helps dramatically with readability. I think some believe one-liners look cooler.

Me every time I hit "submit"

I am very impressed you managed this in one line! /s

I'm so jealous, I tried coming up with a formula for way too long. I'm kicking myself seeing how "simple" it was.

me too ;)

They locked me in a room