program to find first non repeating element in c language??

Question

input :- swiss
output:- w

Answer 1

https://www.geeksforgeeks.org/given-a-string-find-its-first-non-repeating-character/

Answer 2

without pointers (return 0 if no characters found)

char repeat(char * s){
size_t i = 0, j = 0;
while(s[i] && s[j]){
j = i + 1;
while(s[j] && s[j] != s[i]){
j++;
}
++i;
}
return s[i];
}

Answer 3

without using pointer??