Remove Duplicate Characters from a String

Code

#include <stdio.h>
#include <stdint.h>

void remove_duplicates(char *str) 
{
	//Your logic here
    char *a = str;
    char *b = str;
    char *c ;
    char mark = 0x1;

    while(*a)
    {
        b = (a+1);
        while(*b)
        {
            if(*a == *b)
            {
                c=b;
                while(*c)
                {
                    *c = *(c+1);
                    c+=1;
                }
            }
            b++;
        }
        a++;
    }

}

int main() {
    char str[101];
    fgets(str, sizeof(str), stdin);

    // Remove newline
    uint8_t i = 0;
    while (str[i]) {
        if (str[i] == '\n') {
            str[i] = '\0';
            break;
        }
        i++;
    }

    remove_duplicates(str);
    printf("%s", str);
    return 0;
}

Solving Approach