Remove Duplicate Characters from a String

Code

#include <stdio.h>
#include <stdint.h>
#include <string.h>
void remove_duplicates(char *str) {

	//Your logic here
    int k = 0,freq[256] = {0};
    for(int i = 0;str[i] != '\0';i++)
    {
        unsigned char ch = str[i];
        if(freq[ch] == 0)
        {
            freq[ch] = 1;
            str[k++] = str[i];
        }
    }
    str[k] = '\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