Remove Duplicate Characters from a String

Code

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

void remove_duplicates(char *str) {
	//Your logic here
    char m[256] = {0};
    int w = 0;
    int r = 0;
    while(str[r]){
        if (!m[str[r]]){
            m[str[r]] = 1;
            str[w] = str[r];
            w++;
        }
        r++;
    }
    str[w] = '\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;
}