Remove Duplicate Characters from a String

Code

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

void remove_duplicates(char *str) {
	uint8_t map[0x7f] = { 0 };
    char *pw = str;
    if (!pw)
        return;
    while (*str) {
        if (map[*str]) {
            str++;
            continue;
        }
        map[*str] += 1;
        *pw++ = *str++;
    }
    *pw = '\0';
}

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