How can you remove duplicate characters in a string?

Question

I have to implements a function that takes a string as an input and finds the non-duplicate character from this string.

So an an example is if I pass string str = \"

Answer 1

char *remove_duplicates(char *str) { char *str1, *str2;

if(!str)
    return str;

str1 = str2 = str;

while(*str2)            
{   
    if(strchr(str, *str2)

}