Remove Duplicate Characters from a String

Code

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

void remove_duplicates(char *str) {
	//Your logic here
        int seen[256] = {0};   // To track characters already seen
    int i = 0, j = 0;

    while (str[i] != '\0')
    {
        if (seen[(unsigned char)str[i]] == 0)
        {
            seen[(unsigned char)str[i]] = 1;  // Mark as seen
            str[j] = str[i];                  // Keep character
            j++;
        }
        i++;
    }
    str[j] = '\0';  // End the string
}

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