you are confusing *(s++) and (*s)++. This code would not compile if *s was modified. I agree that not using parentheses for these ambiguous-looking expressions is bad practice

I don't get why he specifies 0 to be unsigned long, and not any other unsigned numeral type (ui, us). Isn't the "size_t" statement sufficient ?

@Davidfranom, please, be careful because this is post increment, i.e. give me the character and only then increment

Doesn't this make that comparison start with the 2nd element of the array?

Exaclty!
Give the character under the current pointer (position) and point the pointer to the next character.
Post Increment.

@Karmotrine, Nice Troll for CS students)))
0ul
(chuckle)

0ul means unsigned long integer 0

if arr_size equals 0, your size_t underflows and you might crash

tho the for without a first argument is disgusting