Remove Duplicate Characters from a String

Code

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

void remove_duplicates(char *str) {
    int check[256] = {0};//initializr the all element with Zero
    int j = 0;
    for(int i =0 ; str[i] != '\0' ; i++){
        char c = str[i];
        if(!check[c]){//check the character is duplicate or not if newcharacter means check[ASCII]=0 Already exist character means check[ASCII]=0;           check[c] = 1;
            str[j] = c;
            j++;
        }
    }
    str[j] = '\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