Remove Duplicate Characters from a String

#include <stdio.h>
#include <stdint.h>
char set[255];
void remove_duplicates(char *str) {
	//Your logic here
    int length = 0;
    while (str[length] != '\0') {
        length++;
    }
    for(int i = 0; i < length; i++){
        set[str[i]]++;
        if(set[str[i]] > 1){
            for(int j = i; j < length; j++){
                str[j] = str[j + 1];
            }
            length -= 1;
            i = i - 1;
        }
    }
}

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;
}