Find the different characters present in a string

Question

Is there any way to find the all the unique characters present in a string without finding all the occurrences of the string ? For example, Let it be s

Answer 1

Sounds uncommon enough that it's not part of the STL.
I'd simply try iterating through the string and creating / incrementing the count of numbers in a Hashset. Then, grab all the Keys to determine unique values. Good Luck